Announcing Azure Linux on WSL - Beta
What is Azure Linux? Azure Linux is Microsoft's internal Linux distribution, designed and maintained to support Azure-scale cloud workloads. Today, Azure Linux runs across: Azure infrastructure Azure Kubernetes Service (AKS) Containerized workloads Edge scenarios Azure-hosted services With WSL support, Azure Linux now reaches another important environment: the developer workstation. Why Bring Azure Linux to WSL? A Consistent Path from Development to Production Developers often build in WSL and deploy to Azure. Differences in Linux distributions, packages, dependencies, configurations, and runtime behaviour can create environment drift and late-stage issues. One of the biggest challenges in modern development is environment drift. Teams often: Develop on one Linux distribution Test on another Deploy to something slightly different in production Azure Linux on WSL removes that gap. By bringing Azure Linux directly to the developer machine, teams can: Validate behaviour using production-aligned configurations Reproduce issues more reliably Reduce time spent debugging cross-environment differences The result: a faster, more consistent, and more predictable path from code to cloud. Azure Linux Across the Development Lifecycle Azure Linux already powers millions of cores across Azure. WSL now extends it to the start of the software delivery lifecycle, enabling teams to use one Microsoft-supported Linux foundation across development, testing, and production. Developers can use familiar tools such as VS Code and Git locally, then deploy to Azure targets including virtual machines, AKS, and containers. Not a Desktop OS and That’s Intentional Azure Linux on WSL is not designed to be a desktop Linux experience, and that’s by design. There’s no focus on GUI environments or replacing Windows on the laptop. Instead, Azure Linux remains what it was built for: A server-side operating system Optimised for cloud and container workloads Designed to run reliably at scale in Azure WSL simply makes that environment accessible locally, because today, developer machines increasingly need to mimic production. Getting Started Azure Linux on WSL integrates with standard WSL workflows: Enable WSL on your Windows machine Install Azure Linux by following the steps under the GitHub README documentation. Launch and start building in a production-aligned environment Within minutes, you have a fully functional Azure Linux setup on your local system. Start Building Azure Linux on WSL represents another step in making Azure Linux available wherever developers work. By bringing the same Microsoft-supported Linux distribution from Azure infrastructure to developer workstations, teams can build, test, and deploy using a more consistent foundation throughout the development lifecycle. To learn more about Azure Linux on WSL, see the Overview of Azure Linux on Windows Subsystem for Linux. When you're ready to get hands-on, follow the Azure Linux 4.0 on WSL getting started guide. Try it out and experience a more consistent path from local development to production.From Policy to Practice: Built-In CIS Benchmarks on Azure - Flexible, Hybrid-Ready
Security is more important than ever. The industry-standard for secure machine configuration is the Center for Internet Security (CIS) Benchmarks. These benchmarks provide consensus-based prescriptive guidance to help organizations harden diverse systems, reduce risk, and streamline compliance with major regulatory frameworks and industry standards like NIST, HIPAA, and PCI DSS. In our previous post, we outlined our plans to improve the Linux server compliance and hardening experience on Azure and shared a vision for integrating CIS Benchmarks. Today, that vision has turned into reality. We're now announcing the next phase of this work: Center for Internet Security (CIS) Benchmarks are now available on Azure for all Azure endorsed distros, at no additional cost to Azure and Azure Arc customers. With today's announcement, you get access to the CIS Benchmarks on Azure with full parity to what’s published by the Center for Internet Security (CIS). You can adjust parameters or define exceptions, tailoring security to your needs and applying consistent controls across cloud, hybrid, and on-premises environments - without having to implement every control manually. Thanks to this flexible architecture, you can truly manage compliance as code. How we achieve parity To ensure accuracy and trust, we rely on and ingest CIS machine-readable Benchmark content (OVAL/XCCDF files) as the source of truth. This guarantees that the controls and rules you apply in Azure match the official CIS specifications, reducing drift and ensuring compliance confidence. What’s new under the hood At the core of this update is kompli - a lightweight, open-source module developed by the Azure Core Linux team. It evaluates Linux systems directly against industry-standard benchmarks like CIS, supporting both audit and, in the future, auto-remediation. This enables accurate, scalable compliance checks across large Linux fleets. Here you can read more about kompli. Dynamic rule evaluation The new compliance engine supports simple fact-checking operations, evaluation of logic operations on them (e.g., anyOf, allOf) and Lua based scripting, which allows to express complex checks required by the CIS Critical Security Controls - all evaluated natively without external scripts. Scalable architecture for large fleets When the assignment is created, the Azure control plane instructs the machine to pull the latest Policy package via the Machine Configuration agent. kompli is integrated as a light-weight library to the package and called by Machine Configuration agent for evaluation – which happens every 15-30minutes. This ensures near real-time compliance state without overwhelming resources and enables consistent evaluation across thousands of VMs and Azure Arc-enabled servers. Future-ready for remediation and enforcement While the Public Preview starts with audit-only mode, the roadmap includes per-rule remediation and enforcement using technologies like eBPF for kernel-level controls. This will allow proactive prevention of configuration drift and runtime hardening at scale. Please reach out if you interested in auto-remediation or enforcement. Extensibility beyond CIS Benchmarks The architecture was designed to support other security and compliance standards as well and isn’t limited to CIS Benchmarks. The compliance engine is modular, and we plan to extend the platform with STIG and other relevant industry benchmarks. This positions Azure as a platform for a place where you can manage your compliance from a single control-plane without duplicating efforts elsewhere. Collaboration with the CIS This milestone reflects a close collaboration between Microsoft and the CIS to bring industry-standard security guidance into Azure as a built-in capability. Our shared goal is to make cloud-native compliance practical and consistent, while giving customers the flexibility to meet their unique requirements. We are committed to continuously supporting new Benchmark releases, expanding coverage with new distributions and easing adoption through built-in workflows, such as moving from your current Benchmark version to a new version while preserving your custom configurations. Certification and trust We can proudly announce that kompli has met all the requirements and is officially certified by the CIS for Benchmark assessment, so you can trust compliance results as authoritative. Minor benchmark updates will be applied automatically, while major version will be released separately. We will include workflows to help migrate customizations seamlessly across versions. Key Highlights Built-in CIS Benchmarks for Azure Endorsed Linux distributions Full parity with official CIS Benchmarks content and certified by the CIS for Benchmark Assessment Flexible configuration: adjust parameters, define exceptions, tune severity Hybrid support: enforce the same baseline across Azure, on-prem, and multi-cloud with Azure Arc Reporting format in CIS tooling style Supported use cases Certified CIS Benchmarks for all Azure Endorsed Distros - Audit only (L1/L2 server profiles) Hybrid / On-premises and other cloud machines with Azure Arc for the supported distros Compliance as Code (example via Github -> Azure OIDC auth and API integration) Compatible with GuestConfig workbook What’s next? Our next mission is to bring the previously announced auto-remediation capability into this experience, expand the distribution coverage and elevate our workflows even further. We’re focused on empowering you to resolve issues while honoring the unique operational complexity of your environments. Stay tuned! Get Started Documentation link for this capability Enable CIS Benchmarks in Machine Configuration and select the “Official Center for Internet Security (CIS) Benchmarks for Linux Workloads” then select the distributions for your assignment, and customize as needed. In case if you want any additional distribution supported or have any feedback for kompli – please open an Azure support case or a Github issue here Relevant Ignite 2025 session: Hybrid workload compliance from policy to practice on Azure Connect with us at Ignite Meet the Linux team and stop by the Linux on Azure booth to see these innovations in action: Session Type Session Code Session Name Date/Time (PST) Theatre THR 712 Hybrid workload compliance from policy to practice on Azure Tue, Nov 18/ 3:15 PM – 3:45 PM Breakout BRK 143 Optimizing performance, deployments, and security for Linux on Azure Thu, Nov 20/ 1:00 PM – 1:45 PM Breakout BRK 144 Build, modernize, and secure AKS workloads with Azure Linux Wed, Nov 19/ 1:30 PM – 2:15 PM Breakout BRK 104 From VMs and containers to AI apps with Azure Red Hat OpenShift Thu, Nov 20/ 8:30 AM – 9:15 AM Theatre THR 701 From Container to Node: Building Minimal-CVE Solutions with Azure Linux Wed, Nov 19/ 3:30 PM – 4:00 PM Lab Lab 505 Fast track your Linux and PostgreSQL migration with Azure Migrate Tue, Nov 18/ 4:30 PM – 5:45 PM PST Wed, Nov 19/ 3:45 PM – 5:00 PM PST Thu, Nov 20/ 9:00 AM – 10:15 AM PSTNow Generally Available: Built-in CIS Benchmark Auditing for Linux on Azure
A few months ago, in From Policy to Practice: Built-in CIS Benchmarks on Azure – Flexible, Hybrid-Ready, we introduced a new way to bring Center for Internet Security (CIS) Benchmarks to your Linux estate using Azure Policy with Machine Configuration. It builds on the broader customizable security baseline policies in Machine Configuration capability. Today we're excited to share the next milestone: the audit capability for CIS Benchmarks on Linux is now Generally Available (GA). This release is officially powered by kompli - our native Linux compliance and hardening engine for CIS, STIG, and custom baselines. kompli is the evolution of the engine that drove the preview, now established as the dedicated home for this capability going forward. What "GA" means for you The audit experience is now ready for production use. You can continuously assess your Linux workloads against official, CIS-certified benchmarks - at scale, across Azure and hybrid environments through Azure Arc - and get clear, CIS-style compliance reporting directly in Azure Policy and Azure Resource Graph. If you've read the previous post, the how hasn't changed, so we'll keep this one short: Automated compliance assessment - continuously monitor Linux systems against official CIS benchmarks. Tailored benchmarks - customize evaluations with exceptions and custom parameters, no code changes required. Compliance reporting - detailed, CIS-style reports across your fleet. Hybrid-ready - the same baselines apply to Azure VMs and Arc-enabled servers on-premises or in other clouds. All supported benchmarks are CIS Benchmark Assessment Certified and stay in parity with the content published on the CIS website. Supported distributions and benchmark versions With this release, audit is GA across the following distributions, covering Level 1 + Level 2 Server profiles: Distribution CIS Benchmark Version(s) Profiles Audit Ubuntu 20.04 / 22.04 / 24.04 LTS + Pro v3.0.0 / v2.0.0 + v3.0.0 / v1.0.0 L1 + L2 Server ✓ Red Hat Enterprise Linux 8 / 9 / 10 v3.0.0 + v4.0.0 / v2.0.0 / v1.0.1 L1 + L2 Server ✓ AlmaLinux 8 / 9 v3.0.0 + v4.0.0 / v2.0.0 L1 + L2 Server ✓ Rocky Linux 8 / 9 v2.0.0 + v3.0.0 / v2.0.0 L1 + L2 Server ✓ Oracle Linux 8 / 9 v3.0.0 + v4.0.0 / v2.0.0 L1 + L2 Server ✓ Debian 11 / 12 v2.0.0 / v1.1.0 L1 + L2 Server ✓ SUSE Linux Enterprise 12 / 15 v3.2.1 / v2.0.1 L1 + L2 Server ✓ AKS Optimized Azure Linux 3 v1.0.0 L1 + L2 Server ✓ This GA covers the audit (assessment) capability. Looking ahead, STIG benchmarks are coming next, followed by a granular per-rule auto-remediation capability with dynamic scope assignments. You can run these benchmarks against your own hardened images, against CIS hardened images, and against custom images built on top of vanilla distros — as long as /etc/os-release retains its original content. We're also working with vendors to minimize deviations. Getting started Open Azure Policy in the Azure portal. Under Authoring, select the new Machine Configuration blade. Choose Official Center for Internet Security (CIS) Benchmarks for Linux Workloads, then Modify Settings to pick the distributions you want to assess. Full documentation, including per-distribution rule details, supported parameters, and any known deviations from the official CIS toolset, is available here: Overview: CIS Security Benchmarks for Linux Workloads Per-distribution references: AlmaLinux, Azure Linux, Debian, Oracle Linux, Red Hat Enterprise Linux, Rocky Linux, SUSE Linux Enterprise, and Ubuntu - all linked from the overview page. We're building this with you As part of this GA release, we've also expanded the set of exposed rule parameters compared to the preview - giving you more out-of-the-box customization across rules and distributions. That said, our customer-driven approach still stands: we keep the experience clean by enabling parameters based on real demand, so if there's a rule, benchmark version, or distribution you'd like parameters enabled for - or any feedback on rules, evaluations, or distro coverage - let us know: Open a GitHub issue in the kompli repository Open an Azure support case Try it out, tell us what you think, and help shape what we build next.Announcing the Open-Source Release of ML Video Codec (MLVC)
Video codecs compress video for transmission or storage, reducing bandwidth and storage requirements. MLVC is a modern machine-learning-based codec that uses substantially less bandwidth than conventional codecs, improving streaming and video-call quality—especially on constrained or unreliable networks—while lowering delivery and storage costs. MLVC is the product iteration of DCVC (Deep Contextual Video Compression) family of NVC (Neural Video Codec), open sourced by Microsoft Research since 2021, with improved compression efficiency, real-time performance on commodity Neural Processing Units (NPUs), and cross-platform support. We recently published this work in the paper MLVC: Multi-platform Learned Video Codec for Real-World Deployment. We are releasing the source code because we believe the next generation of video coding will be built openly, and we want the broader community — researchers, video codec engineers, platform vendors, product teams, as well as general developer community — to build it with us. Why MLVC Traditional video codecs (e.g., H.264/AVC, H.265/HEVC) have served the industry for a long time, but each generation requires enormous engineering effort for incremental gains and needs dedicated hardware which takes years to become commonly available. MLVC replaces conventional primitives — motion estimation, transforms, entropy modeling — with end-to-end learned neural compression, trained directly against rate-distortion objectives, and run on general-purpose NPU devices. The table below compares MLVC to popular video codecs, showing its lower bitrate and resulting savings in bandwidth and storage. Resolution vs H.264 vs H.265 360p 87.8% 75.5% 540p 82.7% 65.4% For example, for 360p video at 30 fps, where H.264 requires 1 Mbps, MLVC requires roughly 122 kbps for equivalent quality — about one-eight the bitrate under real-time conditions. The inference compute was kept approximately equal for the 360p and 540p resolutions. These results are based on a P.910 subjective test and are based on the Video Conferencing Dataset (VCD) dataset that we developed and also recently released as an open-source project. The following video demo illustrates the extent of quality enhancement achieved by MLVC relative to H.265/HEVC at the same bitrate of 200kbps (please watch by opening in a new window for better demonstration) \ Beyond video compression efficiency, MLVC also offers: NPU-first design. MLVC is built to run almost entirely on the AI accelerators already shipping in modern devices — Apple Neural Engine, Qualcomm and Intel NPUs — at no more than 50% NPU utilization, leaving NPU headroom for the rest of the system. Real-time execution at the targeted operating points. Demonstrated 540p at 30 fps on Apple, Intel, and Qualcomm hardware. A scaling-law trajectory. Empirically, MLVC's coding efficiency improves with increased model capacity and additional training compute. Content-adaptive behavior out of the box, without hand-tuned Rate Distortion Optimization heuristics. Already running in Microsoft Teams MLVC is more than just a research concept for Microsoft. We are currently rolling it out in Microsoft Teams, where it is being validated on real peer-to-peer video calls with active telemetry and A/B testing. The integration runs alongside fallback to conventional video codecs for hardware or reliability constraints — the kind of mixed-environment deployment that real products need. The scaling and reliability insights from this rollout are shaping the codec and its roadmap. We welcome your contributions We can not cover every use case, every device class, or every content domain by ourselves. That is why we are open sourcing MLVC. If you work on: Streaming, Video On Demand (VOD), or live broadcast Real-time communication and conferencing Cloud gaming or remote rendering Surveillance, drones, or robotics Mobile capture, Augmented Reality (AR) / Virtual Reality (VR), or volumetric video Codec hardware, NPUs, or inference runtimes We would love your help. Contributions of all kinds are welcome, including model improvements, training recipes, new platform ports and conversion targets, runtime backends, domain-specific fine-tunes, evaluation tooling, bug reports, and feedback on what is missing for your scenario. We particularly welcome platform ports that expand NPU coverage and efficiency improvements that push the rate-distortion frontier. What's in the release The MLVC repository is available at https://github.com/microsoft/mlvc and shared under the MIT License. It includes: MLVC model source code of the full network architecture. Trained model weights ready to run. Training scripts used to produce shipping models. Training data collection documentation to help reproduce and improve MLVC. Platform conversion scripts to target different NPUs and runtimes. Issues and pull requests will be open from day one. A follow-up release will add a C++ codec library, simplifying integration into real-world applications. Where we're heading Our long-term goal with MLVC is to create an open, learned video codec that meets or exceeds the coding efficiency of the best conventional codecs across the full range of video content, runs efficiently on the AI hardware already shipping in client and cloud devices, scales with compute the way modern ML systems do, and evolves in the open at the pace of the ML community rather than the pace of standardization cycles. In the near term that means stabilizing 540p real-time performance, expanding hardware coverage, and improving loss resilience. In the medium term: higher resolution, e.g., 1080p, and broader streaming scenarios. In the long term: an open video codec ecosystem that meaningfully replaces legacy stacks where it makes sense to. We can't create the future of MLVC alone. We're glad you're here, and we are looking forward to building the next-generation video codec with you. Who are we MLVC is brought to you by the following awesome folks working on the project at Microsoft: Ross Cutler, Ando Saabas, Tanel Pärnamaa, Ardi Loot, Haiyan Xie, Lauri Ehrenpreis, Andrei Znobishchev, Martin Lumiste, Evgenii Indenbom, Yan Lu, Bin Li, Jiahao Li, Naba Kumar, Babak Naderi, Juhee Cho, Badal Yadav, Jinxin Zhou, Tianyu Ding, Patrick Gregory. — The MLVC Team, MicrosoftIntroducing kars - an Agent Reference Stack for Kubernetes
kars is an open-source, Kubernetes-native runtime for AI agents on Azure. It treats every agent as untrusted code - per-pod kernel isolation, zero credentials in the agent process, and an end-to-end encrypted inter-agent mesh - and governs agents on any framework with one set of Kubernetes policies via the Microsoft Agent Governance Toolkit. kars dev runs a governed agent on your laptop in minutes.What IT teams need to know about Linux Secure Boot certificates expiring in 2026
If your organization does not use UEFI Secure Boot on Linux systems, this transition does not affect your boot path. You can stop reading now. If you do use Secure Boot, here is what you need to know. The Microsoft Corporation UEFI CA (Certificate Authority) 2011 expires on June 27, 2026 (June 26 local time in some time zones). Expiration alone does not stop anything from booting and does not render a system insecure. Existing 2011-signed shims keep working on systems that still trust the 2011 CA. The real risk is narrower: once an operating system vendor ships a shim signed only by the Microsoft UEFI CA 2023, any system whose firmware does not already trust the 2023 CA will fail to boot. The work for you is to confirm, before that update reaches your systems, that your systems trust the 2023 CA. If you want the history of why a Microsoft certificate sits in the Linux Secure Boot path at all, skip to the end. Terms used in this post You may see three Microsoft Secure Boot certificate authorities discussed in 2026 guidance. This post focuses on the Microsoft UEFI CA 2011, which is the CA used for third-party UEFI boot applications such as the Linux shim. The other expiring Microsoft Secure Boot certificates are the Microsoft Corporation KEK CA 2011, which is used to authorize updates to Secure Boot databases, and the Microsoft Windows Production PCA 2011, which is used for Windows boot components. Windows systems have a separate update path for those certificates; this post covers only the Linux boot chain. The 2023 update also separates two uses that were both covered by the Microsoft UEFI CA 2011. The Microsoft UEFI CA 2023 is for third-party UEFI boot applications, including the Linux shim. The Microsoft Option ROM UEFI CA 2023 is for third-party option ROMs, such as firmware on some add-in cards. This post is about the Linux bootloader path, but physical systems that rely on signed option ROMs may need to check that path too. Microsoft began returning 2023-signed Linux shim binaries to operating system vendors in October 2025, and since then a submitted shim comes back signed by both the 2011 CA and the 2023 CA. Once the 2011 CA expires, Microsoft can only sign with the 2023 CA. In UEFI Secure Boot terminology, db is the allowed signature database, dbx is the forbidden or revoked signature database, and KEK contains keys that can authorize updates to db and dbx . SBAT is a shim ecosystem mechanism for revoking boot components by generation. SBAT is related to Secure Boot revocation, but it is separate from the CA expiration itself. For brevity, the rest of this post uses operating system vendor to include Linux distributions and other vendors that ship and support Linux boot components. Microsoft returns signed shims to that submitting operating system vendor. It does not push shim updates to end users or IT departments. Those reach systems through the normal operating system, package, image, or platform update channels. What is not happening Expiration is not revocation, and it does not cause an immediate boot failure. The 2011 CA expiring does not make existing 2011-signed shims stop booting on June 27, 2026. UEFI Secure Boot validates a signature against the trust database and revocation state, not against the certificate's validity period. The image-validation process in the UEFI specification bases the decision on whether the image's hash or signing certificate is present in the authorized database ( db ) and absent from the forbidden database ( dbx ). It does not check whether the certificate has expired. Firmware bugs are always possible, but expiration by itself should not invalidate an already-signed shim. There is also no current plan to revoke the Microsoft UEFI CA 2011. Expiration means Microsoft can no longer sign new binaries with that certificate. Revocation would mean telling systems not to trust binaries signed with it. Revocation is not the plan. For the same reason, do not remove the 2011 CA from a system's Secure Boot db . Removing it strips that trust path. Removal is not required for this transition, and existing boot components may still depend on the 2011 CA. No operating system vendor has to move to a 2023-signed shim on the expiration date. An operating system vendor may keep shipping a 2011-signed shim (if one is available), ship a 2023-only shim, or ship one carrying both signatures. That decision belongs to the operating system vendor. What can break The failure case is a mismatch between the shim signature and the firmware trust database. The moment to worry about is not the expiration date. It is when a system first receives a 2023-only shim. That leaves a remediation window: the time between the expiration date and the first 2023-only shim reaching a given system. How long it lasts depends on your operating system vendor's packaging decisions, any security fix that forces a new shim release, and how easily you can update firmware or VM Secure Boot state on the affected platforms. The transition comes down to one table: Firmware trust database 2011-only shim 2023-only shim Dual-signed shim 2011 CA only Boots, but depends on continued 2011 trust Does not boot Should boot 2023 CA only Does not boot Boots Should boot Both 2011 and 2023 CAs Boots Boots Boots The table is deliberately simple. Real systems also have dbx revocations, SBAT policy, firmware bugs, operating system vendor packaging choices, and platform-specific update paths. But this is the core compatibility problem. Dual-signed shims help bridge the transition, because the same shim can validate through either CA. However, they are not a guarantee. Some firmware mishandles multiple signatures and evaluates only one of them, revocation and vendor support still apply, and the operating system vendor decides whether to ship and support a dual-signed shim at all. This kind of failure happens early, before the operating system loads. Recovery means restoring a trusted boot path or following your operating system, hardware, or platform vendor's recovery guidance. It is not a package rollback inside a running system. Who should pay closest attention This transition matters most where the operating system, firmware, and update path may not move together. If you run a maintained operating system on maintained hardware or a maintained virtualization platform, the normal vendor update path may handle most of it. Closer attention is worthwhile where that path is missing, delayed, customized, or hard to validate. Older hardware is the first case. Some systems need a firmware update before they can trust the 2023 CA, and support can vary by model even within one hardware vendor's portfolio. Check each model you operate rather than assuming one answer covers the fleet. Long-lived virtual machines are the second. VM firmware is still firmware. A VM's Secure Boot state depends on when it was created, which platform firmware it uses, and which UEFI variables have changed since. Firmware is not just another package update, so a long-lived VM may never have received the relevant firmware or database updates unless the administrator or platform applied them. Your cloud or virtualization provider should be able to say how the 2023 CA is handled for new VMs, existing VMs, and imported or custom images. For Azure Trusted Launch and Confidential VMs specifically, Microsoft has published guidance on identifying and updating affected instances. Older operating system releases need more careful validation. Some lack current Secure Boot tooling, current fwupd daemon behavior, or a supported path for updating UEFI trust databases. A command that works on one release may not be supported on another. Custom fleets are their own category: systems built from custom images, frozen package mirrors, pinned bootloader versions, or local Secure Boot policy changes. The more an environment differs from the vendor's default update path, the more you need to verify the actual firmware trust database and installed shim directly. Smaller operating system vendors and long-tail distributions are worth checking too, especially if they submit shim updates infrequently or have not finished their 2023 signing transition. No single authoritative public list tells you which releases have completed this work. Who is responsible for what There is no single Linux Secure Boot owner who can make every system safe for the transition. The operating system vendor controls which shim and boot components it ships. It also controls whether its update process checks the firmware trust database before installing a 2023-only shim. The Linux community runs a community-driven shim-review process for shim submissions. That process is the primary review gate before an operating system vendor requests a Microsoft signature. It is not a support channel for individual systems or fleets. The hardware vendor, firmware vendor, or virtual machine platform controls which trust anchors are present by default and how firmware updates are delivered. In a physical machine, that may mean a BIOS or firmware update. In a VM, it may mean platform firmware defaults, guest-visible UEFI variables, or a provider-specific remediation process. Microsoft controls the Microsoft UEFI signing service and the Microsoft UEFI CAs. After shim-review approval, Microsoft verifies the submitter's relationship to the operating system vendor, runs some additional checks, signs submitted shims, and returns the signed artifacts to the submitting operating system vendor. Microsoft does not choose when each operating system vendor ships a new shim to its customers. Your organization controls the systems it administers. In practice, that means checking whether Secure Boot is enabled, checking which certificates are trusted, following guidance from the relevant operating system vendor, and following guidance from the hardware vendor or VM provider. This is why the right answer for any specific system depends on its operating system vendor, hardware vendor, and platform. This post explains the model. Only those vendors can tell you what is supported for your systems. What to check The exact commands vary by operating system vendor, package set, and platform. Treat the examples below as illustrations, not guaranteed instructions for every Linux system. IT departments should validate commands against vendor documentation before using them in production automation. At fleet scale, the useful starting point is an inventory rather than a one-time manual check. Useful fields include whether Secure Boot is enabled, which Microsoft UEFI CAs are present in the firmware trust database, which CA signed the installed shim, the operating system release, the hardware model or VM platform, the update channel, and whether the system comes from a custom image or vendor image. Set up representative canary systems before any broad rollout. A canary set should cover the differences that matter in your fleet: hardware model, VM platform, operating system release, image lineage, and update channel. The aim is to avoid discovering a firmware or shim mismatch for the first time during a broad production update, not to build a new certification program. First, check whether Secure Boot is enabled: sudo mokutil --sb-state If Secure Boot is disabled, this certificate transition does not affect that system's current boot path. Next, check which Microsoft UEFI CAs are in the firmware trust database: sudo mokutil --db Look for entries such as: Microsoft Corporation UEFI CA 2011 Microsoft UEFI CA 2023 If both are present, the system is prepared for a future 2023-signed shim. If only the 2011 CA is present, check guidance from the relevant operating system vendor and platform provider before accepting a 2023-only shim update. On physical systems, also check whether the platform relies on signed third-party option ROMs. Those may require the Microsoft Option ROM UEFI CA 2023 in addition to the Microsoft UEFI CA 2023 used for boot applications. This is another reason hardware guidance can vary by model. Administrators can also inspect the signature on the shim currently installed on a system. On Enterprise Linux and related distributions, pesign is often used: sudo dnf install pesign sudo pesign -S -i /boot/efi/EFI/<vendor-or-distribution>/shimx64.efi On Debian, Ubuntu, and related distributions, sbverify from sbsigntools is often used: sudo apt install sbsigntools sudo sbverify --list /boot/efi/EFI/<vendor-or-distribution>/shimx64.efi The path to shim may differ. Some systems use a different EFI path, a different architecture suffix, or a different bootloader arrangement. Vendor documentation is the right source for exact commands. How updates may be delivered Many operating system vendors use the Linux Vendor Firmware Service (LVFS) and fwupd for firmware-related updates, including some UEFI Secure Boot database updates. Not every vendor enables the same tooling, and not every platform supports the same update mechanism. Common examples include: sudo fwupdmgr update sudo fwupdmgr security sudo fwupdmgr get-devices Some systems may require a firmware update from the hardware vendor. Some may support a standalone UEFI database update. Some may not support a safe standalone update at all. Some hardware and firmware vendors block standalone database updates because earlier failures showed that the update could break systems. Updating the Secure Boot allowed signature database ( db ) also depends on authorization from keys in KEK . That is one reason these updates often require cooperation from the firmware, hardware, or VM platform vendor. Administrators should not assume that possession of a certificate file is enough to update a system safely. Do not force a Secure Boot database update just because a command exists. Follow the guidance for the specific hardware, VM platform, or operating system vendor. Forcing an update can force a physical reboot of a machine or destroy the system. After the first inventory pass, keep watching the operating system vendor's security advisories and bootloader package updates. Questions for your vendors The right questions depend on the system, but these are the kinds of answers IT departments should look for from operating system vendors, hardware vendors, and VM providers: Does this operating system release currently ship a 2011-signed, 2023-signed, or dual-signed shim? If the vendor plans to ship a 2023-only shim, will the update process check whether the system trusts the 2023 CA before installing it? How is the Microsoft UEFI CA 2023 delivered for this hardware model, VM platform, or image? Is a standalone Secure Boot database update supported, or must the update arrive through a firmware update? Does support vary by hardware model, firmware version, VM generation, image type, or operating system release? What should administrators monitor for shim, GRUB, SBAT, db , KEK , or dbx updates related to this transition? What is the recommended validation path before broad deployment? What is the supported recovery path if a system receives an incompatible shim or firmware update and fails to boot? What to do now If an IT department administers Linux systems that use Secure Boot, the useful work is straightforward: Use the checks above to inventory Secure Boot state, trusted CAs, and installed shim signatures across representative systems. Identify the parts of the fleet most likely to diverge from default vendor paths, including older hardware, long-lived VMs, older operating system releases, custom images, and pinned bootloader packages. Read operating system, hardware, and VM provider guidance before accepting 2023-only shim updates or applying firmware and Secure Boot database updates. Test representative canary systems before rolling out shim or firmware changes broadly. Monitor operating system vendor advisories for shim and bootloader updates related to the transition. Avoid forcing low-level firmware or UEFI variable updates unless vendor guidance says to do so. How Linux got here UEFI Secure Boot was introduced to let firmware verify boot components before executing them. The firmware contains a trust database. If a bootloader is signed by a trusted certificate and is not blocked by revocation policy, the firmware can execute it. In the PC ecosystem, Microsoft has long operated the signing infrastructure used by Windows and by many third-party UEFI boot components. Linux operating system vendors do not have Microsoft sign the Linux kernel directly. Instead, they use a small first-stage bootloader called shim. The Linux shim is signed by Microsoft so firmware will start it. The shim then validates the next boot component, usually GRUB or another vendor-controlled bootloader, using keys controlled by the operating system vendor, not Microsoft. That structure lets Linux operating system vendors participate in the UEFI Secure Boot ecosystem while keeping control over their own boot chains. The shim code is developed publicly, and shim signing uses the community-run shim-review process before the Microsoft signing step. That split is important. The Linux community reviews shim submissions, and Microsoft operates the signing service that applies a signature firmware will trust. The certificate rotation affects this first handoff. Firmware must trust the CA that signed shim. If a future shim is signed only by the 2023 CA, the firmware needs the 2023 CA in its trust database. A system that keeps booting with a 2011-signed shim is not automatically broken or insecure on the expiration date. A system that moves to a 2023-signed shim needs to trust the 2023 CA; plan for that transition.
Announcing Azure Linux 4.0: Purpose-Built for Azure, Now in Public Preview
Today at Microsoft Build, we're announcing the public preview of Azure Linux 4.0 - Microsoft's first party Linux distribution, purpose-built for Azure. Azure Linux 4.0 is available now for Azure Virtual Machines, VM Scale Sets, and container images – with Azure Kubernetes Service (AKS) support and Windows Subsystem for Linux (WSL) coming soon after. Why Azure Linux Running Linux on Azure often involves a mix of distributions - one for VMs, another for Kubernetes nodes, a third for container base images, and sometimes something different on developer machines. That flexibility is powerful, but it can also introduce operational overhead: multiple patch schedules to coordinate, multiple security baselines to validate, and more moving parts for SRE and security teams to stay ahead of. A more consistent baseline - especially one with a smaller footprint - can help reduce exposure and simplify day‑to‑day maintenance Azure Linux was built with that principle in mind: a single, Microsoft-supported Linux foundation designed to work across every Azure compute surface. From kernel updates to CVE patches, Azure Linux is built and maintained by Microsoft with a predictable update cadence designed around Azure infrastructure. Azure Linux is included with Azure compute at no additional cost. What Is Azure Linux 4.0 Azure Linux is a Fedora-derived, RPM-based Linux distribution built and maintained by Microsoft. It is open source, free to use, and optimized specifically for Azure. Minimal by choice, secure by default; Azure Linux ships only the packages required for cloud workloads. Azure Linux is built exclusively for cloud and server workloads, it is not intended to support desktop usage or GUI applications. Azure Linux already powers millions of cores across Azure's internal services, including AKS, Azure SQL, Azure Cosmos DB, and many others. With 4.0, we're bringing the same OS - same security posture, same performance tuning, same operational simplicity - to every Azure customer. When Azure Linux 4.0 reaches General Availability, you can expect seamless integration with the Azure services you already rely on, including: Microsoft Defender for Cloud - vulnerability assessment and threat detection Azure Monitor - telemetry, logs, and performance monitoring Azure Migrate - discovery and migration tooling Trusted Launch and Secure Boot - hardware-rooted security Azure Portal, CLI, ARM, Bicep, Terraform, Ansible -deploy and manage with your existing tools What's New in Azure Linux 4.0 Component Version What Changed Kernel 6.18 LTS Azure-tuned with new hardware drivers, improved Hyper-V integration, GPU/AI accelerator support Package Manager dnf5 Complete rewrite from python to reduce dependencies, faster package resolution, lower memory usage glibc 2.42 This includes performance improvements in string ops, memory allocation, thread handling OpenSSL 3.5 This release includes post-quantum cryptography support, improved QUIC support, and other crypto updates. systemd 258 Faster boot sequences, improved service management Python 3.14 JIT compiler, new syntax features RPM 6.0 Modernized database backend, improved signature verification FIPS 140-3 In progress Will be available at GA. Azure Linux on Virtual Machines Deploy Azure Linux 4.0 directly from the Azure Marketplace on any Azure VM or VM Scale Set. Azure Linux images are validated across Azure VM SKUs and tuned for Azure compute, storage, and networking delivering faster VM startup and provisioning with a reduced package footprint. Whether you're running web applications, databases, or GPU-accelerated AI/ML workloads, Azure Linux provides a consistent, secure foundation with no additional OS licensing cost. You pay only for the underlying Azure compute resources. Deploy your first Azure Linux VM in minutes from the Azure Marketplace. Azure Linux on Azure Kubernetes Service Azure Linux has been the container host for AKS since 2023, already powering mission-critical Kubernetes workloads at massive scale. With 4.0, we're also introducing Azure Container Linux (ACL) an immutable, container optimized variant for environments with stricter security and compliance requirements. To learn more about Azure Container Linux, see ACL blogpost. Azure Linux (General purpose) Azure Container Linux (ACL) Update model Package-based (dnf5) Image-based, immutable, auto-updating Customization Full package management Locked-down, minimal surface Best for General AKS workloads Regulated, high-security environments SELinux Supported Enforcing by default Both options share the same kernel, security update cadence, and Azure integration; fully supported by Microsoft, end to end. Azure Linux Container Images Build and run containerized applications on Microsoft-maintained base images from the same Azure Linux supply chain. One Linux experience from VMs to containers with the same security updates, same compliance posture, and same operational model. Image Type Use Case Base Full flexibility - install any packages you need Runtime (Python, Node.js, Java, .NET) [Not available at Preview] Pre-configured for your language stack Distroless Minimal attack surface - no shell, no package manager All images are available on Microsoft Container Registry (MCR) and follow the same monthly security update cadence as Azure Linux VM images. Azure Linux on WSL Familiar Linux, optimized for Azure. Develop locally on the same Linux you run in production. Azure Linux for Windows Subsystem for Linux brings your production OS to your developer workstation, eliminating environment drift and giving your team a consistent dev-to-cloud workflow. Azure Linux for WSL will be available shortly after Build. Secure by Default, Backed by Microsoft Security is not an add-on in Azure Linux; it's foundational. Built with security in mind from day one, Azure Linux applies defense-in-depth from the kernel through to the supply chain. A reduced package footprint means fewer vulnerabilities to manage, and Microsoft's ownership of the full supply chain enables fast-track CVE response. Below is a summary of security capabilities that you should expect to see in Azure Linux at the time of general availability. Capability Details Secure Boot & Trusted Launch Signed shim, GRUB, kernel, and systemd-boot. SELinux Supported on all images. Enforcing by default. FIPS 140-3 Certification in progress. Built-in crypto module support. Kernel hardening ASLR, stack protection, seccomp, systemd service sandboxing. Supply chain security All packages and repos cryptographically signed. SBOMs published. Identity Entra ID SSH support. CVE response Microsoft-owned supply chain enables fast-track Critical/High CVE patches. Lifecycle LTS kernels maintained for lifetime of the distribution. Day-1 Ecosystem Partner Support Azure Linux already has validated support from a broad ecosystem of security, monitoring, networking, and data partners via AKS and VM support: Dynatrace — Application performance monitoring and observability Aquasec – database platform support Qualys — Vulnerability management, compliance scanning, and asset inventory Isovalent — eBPF-powered networking, security, and observability via Cilium Elastic — Log analytics, infrastructure monitoring, and SIEM/XDR Upwind — Runtime cloud security and behavioral threat detection SAP — Enterprise workload certification for S/4HANA and NetWeaver Databricks — Data and AI platform powering lakehouse workloads at scale Arm — Native Arm64 architecture support for cost-efficient cloud compute Proven at Scale Azure Linux isn't new; it has been running production workloads at massive scale across Azure's internal services and early adopters. Azure Linux has been powering production workloads at massive scale since 2022 across AKS, Azure SQL, Azure Cosmos DB, and other core Azure services along with LinkedIn and Databricks. With version 4.0, we're building on that proven foundation with a modernized stack, expanded compute surface support, and a new Fedora-derived base, bringing the same reliability our internal services depend on every Azure customer. Databricks Databricks migrated over 100,000 VMs and more than 1 million CPU cores to Azure Linux with zero customer-facing incidents. The migration eliminated separate hardened images by leveraging Azure Linux's built-in FIPS support and delivered measurable performance gains: 27% faster image pull times and approximately 5% faster query execution across their serverless compute fleet. LinkedIn LinkedIn completed a major stack upgrade, migrating to Azure Linux 3 across their infrastructure. The transition enabled adoption of configuration as code and modern kernel integration, resulting in a more resilient, secure, and future-proof environment. LinkedIn's Grid team reported significant performance improvements following the migration. Predictable Lifecycle and Updates Patch faster. Operate simpler. Azure Linux follows a clear, predictable lifecycle designed for teams running large Azure fleets: LTS kernel - Maintained with monthly CVE backports. HWE kernels - Introduced annually for new hardware platforms, GPU, and AI accelerator enablement. Predictable updates - Packages (language runtimes, tools) are refreshed in predictable windows. Between windows, only critical/high CVE patches are backported. Monthly security updates - Predictable cadence for all supported packages. For full details on the lifecycle model, kernel tracks, and package tiers, see the Azure Linux Release Cadence and Lifecycle documentation. Get Started Azure Linux 4.0 is available now in public preview. Choose the path that fits your workload: Scenario How to Start Azure Virtual Machines Deploy from Azure Marketplace via Portal, CLI, ARM, Bicep, or Terraform Azure Kubernetes Service [Not available at Preview] Set --os-sku to AzureLinux when creating a node pool Container Images Pull from Microsoft Container Registry (MCR) WSL [Not available at Preview] wsl --install -d AzureLinux Learn More //Build Session: Build, deploy, and run Linux workloads on Azure Azure Linux documentation To learn more and get started, visit aka.ms/AzureLinuxProduct Azure Linux on GitHub Release notes Joining the ISV partner program: AzureLinuxPartners@microsoft.com We're excited to put Azure Linux in your hands. Try it today and let us know what you think.
Introducing Azure Container Linux (ACL)
Today at Microsoft Build 2026, we’re announcing the general availability of Azure Container Linux (ACL): a secure, immutable container host designed to help platform teams run Kubernetes workloads at scale on Azure Kubernetes Service (AKS) with greater consistency, reduced operational overhead, and a stronger default security posture. This release builds on Microsoft’s long-standing commitment to the Flatcar Container Linux ecosystem as a foundation for secure, minimal, and container-optimized operating systems. This commitment includes the acquisition of Kinvolk in 2021, bringing deep expertise in Flatcar development and cloud-native systems into Azure, and the subsequent donation of Flatcar to the Cloud Native Computing Foundation (CNCF), ensuring its continued growth as a community-driven project. Flatcar has played a critical role in helping customers run cloud-native infrastructure at scale, introducing an immutable, minimal OS model that reduces configuration drift, minimizes attack surface, and simplifies lifecycle management. As customer needs continue to grow, there is an increasing demand for deeper integration with cloud platforms, stronger default security enforcement, and a more tightly managed supply chain experience in managed environments like AKS. Building on this foundation, Azure Container Linux (ACL) represents the next evolution of this approach. ACL is intentionally built downstream of Flatcar to preserve compatibility with its ecosystem and leverage its mature, battle-tested design. ACL integrates Azure Linux binaries as the core foundation, providing consistency and compatibility with other Azure Linux use cases (including Azure Linux VMs), while bringing enterprise-hardened security and supportability into the platform. Looking ahead, ACL will further incorporate optional advanced code integrity capabilities from Azure Linux with OS Guard. We remain committed to the Flatcar community and will continue contributing innovations upstream while bringing a fully managed, enterprise-ready product to customers through ACL. Why a Trusted, Immutable Host Model Matters for AKS As Kubernetes adoption scales, platform teams face increasing complexity in managing node-level consistency, security, and lifecycle operations across large fleets. Traditional OS models introduce challenges such as: Configuration drift across nodes, leading to inconsistent behavior and harder-to-debug issues Fragmented update mechanisms that increase operational overhead and risk during upgrades Expanding attack surface due to unnecessary packages and mutable system state Limited visibility and guarantees around the provenance and integrity of OS components In managed environments like AKS, these challenges are amplified as teams look to operate clusters reliably at scale while meeting stricter security and compliance requirements. Azure Container Linux: Built for Consistency and Trust ACL addresses these challenges with a fully image-based operating system model that eliminates configuration drift, ensuring consistent behavior across nodes. Updates are delivered through AKS node image upgrades, providing a consistent and repeatable way to roll out OS changes across clusters without relying on in-place modifications. By standardizing how nodes are built, updated, and operated, ACL helps ensure clusters remain in a known-good, reproducible state over time, even as they scale. Over time, this model will continue to evolve to support A/B update mechanisms to further improve reliability, speed, and operational efficiency. Secure from the Start, and Designed for the Future ACL is engineered with a hardened security posture from the moment it boots. Its immutable design protects the integrity of the operating system, prevents unauthorized changes, and ensures consistent, reproducible behavior across your Kubernetes fleet. By removing unnecessary components and tightly constraining how the system can be modified, ACL reduces the attack surface and provides a strong foundation for running production workloads with confidence. Under the hood, ACL incorporates several safeguards that reinforce its secure-by-default model: Read-only /usr filesystem to prevent tampering with core system components. A minimal package set purpose-built for container workloads, reducing CVE exposure. Mandatory access control with SELinux, enforcing strict least-privilege policies. Trusted Launch using a Unified Kernel Image (UKI) to bundle the kernel, initramfs, and kernel command line into a single signed artifact, ensuring integrity from the earliest stage. Signed Azure Linux RPMs delivered through a trusted, end-to-end Microsoft supply chain. Going forward, we will continue to evolve ACL’s security posture as we bring over additional innovations from Azure Linux with OS Guard. This includes integrating code integrity into the ACL image, using the Integrity Policy Enforcement (IPE) Linux security module, to ensure that only binaries from trusted, signed volumes are allowed to execute. IPE will also extend to container images, ensuring that only binaries matching a trusted signature can be executed from verified dm-verity backed layers. Where applicable, we are committed to contributing these advancements upstream to the Flatcar project, helping strengthen the ecosystem and ensuring that improvements benefit the broader cloud-native community. Differentiating between Azure Container Linux and Existing Container Hosts on AKS AKS now provides multiple generally available Linux OS options, including general-purpose container hosts (Azure Linux and Ubuntu) and an immutable container host (Azure Container Linux). While all options are fully supported by Microsoft, they are designed to address distinct operational and security use cases. The sections below highlight the key differences to help you choose and position the right OS for your scenario. General Purpose OS Azure Container Linux Filesystem Writable (read-write) Immutable (read-only) /usr with dm-verity guarantees Focus on Extensibility, flexibility, and choice. Out of the box security and compliance guarantees. Mandatory Access Control AppArmor (optional) SELinux (enforcing by default)* Secure Boot Optional (supported with certain VM sizes) Supported by default with UKI (Unified Kernel Image) Updates Package and Image based updates supported Only image-based updates supported (A/B update support on the roadmap) *SELinux policies are subject to change over time based on customer feedback. Day‑1 Ecosystem Partner Support Azure Container Linux is launching with support from a broad ecosystem of security, monitoring, networking, and data partners. The following partners are expected to offer support or validated integrations at Day‑1 availability: Dynatrace – application performance monitoring and observability. Aquasec – database platform support on ACL. Qualys - vulnerability, compliance, and container security. Upwind - runtime cloud security and risk prioritization. Elastic - logs, metrics, and observability for Kubernetes. Isovalent – Kubernetes networking, observability, and security powered by eBPF (Cilium). If you’re interested in becoming a supported Azure Container Linux partner, please reach out to: AzureLinuxPartners@microsoft.com What Customers Are Saying Early customer feedback highlights the real‑world impact of Azure Container Linux on improving security posture and operational consistency at scale. “We’ve found working closely with the Microsoft product team throughout the Azure Container Linux preview to be invaluable. The product's immutability, minimal footprint, and built‑in security controls (such as SELinux and Trusted Launch) will strengthen our AKS security posture across every deployment instance in Nationwide. Furthermore, its focus on secure‑by‑design foundations is especially timely as we face advanced threat detection capabilities within the industry.” - Enterprise Container Platform, Cloud - Nationwide Engineered for AKS from Day One Azure Container Linux is deeply integrated with AKS to ensure a seamless operational experience. It is compatible with many critical AKS extensions and add‑ons, and works smoothly with existing application containers and deployment workflows. ACL is available across AMD64 and Arm64 architectures, ensuring consistent behavior across environments, and includes support for GPU-enabled workloads. Enabling ACL is as simple as specifying the following in your node pool configuration: --os-sku AzureContainerLinux Whether you're onboarding new clusters or migrating existing ones, ACL is designed to integrate into your environment with minimal friction. A Clear Path Forward for AKS Preview Users With the release of Azure Container Linux, AKS will transition to offer one unified immutable host offering. This work started with our use of Flatcar Container Linux in Preview and now continues with the GA release of ACL. As part of this release, Flatcar will no longer be available via --os-sku on AKS. Please note, this change applies specifically to the AKS preview experience; Flatcar is not being retired. Later this year we will complete the convergence of our immutable OS offerings by incorporating remaining kernel and runtime features of the current OS Guard preview into ACL. At that time, existing users of OS Guard will receive a guided transition to ACL, ensuring operational continuity while consolidating to a single container host. Get Started with Azure Container Linux ACL is GA and available today for all AKS customers. To begin using ACL in your clusters and explore documentation, best practices, and deployment guidance, visit: aka.ms/azurecontainerlinux ACL represents the future of secure, cloud-optimized Linux on AKS—building on the proven foundation of Flatcar, advancing it with Azure Linux innovations, and contributing back to the open-source ecosystem that customers depend on. We’re thrilled to bring this new foundation to our customers and can’t wait to see what you build with it. Learn More //Build Session: Build, deploy, and run Linux workloads on Azure Azure Container Linux documentation: https://aka.ms/azurecontainerlinux Azure Container Linux on GitHub: https://github.com/microsoft/azure-container-linux Azure Linux product page: https://aka.ms/AzureLinuxProduct Azure Linux documentation: https://aka.ms/azurelinux Joining the ISV partner program: AzureLinuxPartners@microsoft.comFour open source projects to explore at Microsoft Build
Open source is where developers experiment, collaborate, and turn new ideas into tools that others can build on. At Microsoft Build, we’re creating a dedicated space for that energy: the Open Source Zone. This year, the Open Source Zone will bring together maintainers, contributors, and developers working on some of the most interesting open source projects in AI. Whether you’re building agents, experimenting with local models, exploring prompt workflows, or looking for practical ways to bring AI into your development process, this is a place to meet the people behind the projects and see what they’re building. The Open Source Zone is inspired by similar community spaces we’ve hosted at GitHub Universe: hands-on, conversation-driven, and centered on the people and projects moving open source forward. Meet the projects OpenClaw OpenClaw, originally Clawbot, formerly Clawdbot and briefly Moltbot,before landing on its current name (because naming is hard), is a personal AI assistant project built for developers who want more control over how AI agents run across tools, devices, and workflows. Its repository describes it as “your own personal AI assistant” across operating systems and platforms, with support for agent workspaces, skills, and device nodes. It has also become one of the fastest-growing open source projects on GitHub, with over 370,000 stars to date. At the Open Source Zone, attendees can learn how OpenClaw approaches personal agents, extensibility, and local-first experimentation. AutoGPT AutoGPT is one of the best-known open source projects in the autonomous agent space. The project’s mission is to make AI accessible for everyone to use and build on, with tools for building, testing, and delegating work to agents. Visit AutoGPT in the Open Source Zone to learn how the project is evolving agent development, benchmarking, frontend experiences, and practical workflows for building agent-powered applications. Come for the autonomous agents; stay for the very human maintainers. AutoGPT is also a member of GitHub’s Secure Open Source Fund, with a goal of enhancing AI security across the open source ecosystem. Open WebUI Open WebUI is a self-hosted, extensible AI platform for working with large language models. The project supports Ollama and OpenAI-compatible APIs and includes built-in RAG capabilities, making it a strong option for developers and organizations exploring local, private, or provider-flexible AI experiences. At Build, the Open WebUI team will show how developers can run, customize, and extend AI interfaces for their own environments. prompts.chat prompts.chat, formerly Awesome ChatGPT Prompts, is a curated collection of prompt examples for AI chat models. The project is designed to help people discover, share, and build better prompts for modern AI assistants. Created by Fatih Kadir Akın, a GitHub Star from Istanbul, prompts.chat reflects his work at the intersection of open source, developer education, and AI-assisted development. Fatih leads Developer Relations at Teknasyon, has authored books on JavaScript and prompt engineering, and is active in the community as a speaker, organizer, and contributor. Stop by to explore prompt libraries, prompt engineering resources, self-hosting options, and ways the community is making prompting more reusable and collaborative. Register for Microsoft Build Microsoft Build takes place June 2–3, 2026, in San Francisco and online. In-person passes are available, and online registration is free for livestreamed keynote and select session access. Register for Microsoft Build and come visit the Open Source Zone to meet the teams behind OpenClaw, AutoGPT, Open WebUI, and prompts.chat. We’ll see you there. <3Governing AI Agents Against Every OWASP Agentic Risk: A Deep Dive with the Agent Governance Toolkit
AI agents are moving from prototypes to production. They book flights, write code, negotiate contracts, and operate across enterprise systems with minimal human oversight. The attack surface is not theoretical: OWASP has catalogued the top 10 risks specific to agentic applications, and every one of them maps to a real-world failure mode. The Agent Governance Toolkit (AGT) is an open-source, MIT-licensed framework that enforces deterministic governance at runtime, before every tool call, message, and action an agent takes. This is not prompt engineering or guardrails bolted on after the fact. AGT provides policy-as-code enforcement, zero-trust identity, execution isolation, and tamper-evident audit trails across the full agent lifecycle. In this post, we walk through all 10 OWASP Agentic risks with real code from the AGT repository. By the end, you will have concrete examples for every risk category and a clear path to production-grade agent governance. Coverage at a Glance # OWASP Risk AGT Component Key Mechanism ASI-01 Agent Goal Hijack Agent OS Policy Engine + Action Interception ASI-02 Tool Misuse & Exploitation Agent OS Capability Sandboxing + Input Sanitization ASI-03 Identity & Privilege Abuse AgentMesh DID Identity + Trust Scoring ASI-04 Supply Chain Vulnerabilities AgentMesh AI-BOM (Model + Data + Weights Provenance) ASI-05 Unexpected Code Execution Agent Runtime Execution Rings (Ring 0-3) ASI-06 Memory & Context Poisoning Agent OS VFS Policies + CMVK Verification ASI-07 Insecure Inter-Agent Comms AgentMesh IATP + E2E Encrypted Channels ASI-08 Cascading Agent Failures Agent SRE Circuit Breakers + SLOs ASI-09 Human-Agent Trust Exploitation Agent OS Approval Workflows + Quorum Logic ASI-10 Rogue Agents Agent Runtime Kill Switch + Ring Isolation + Merkle Audit ASI-01: Agent Goal Hijack The risk: Attackers manipulate the agent's objectives via indirect prompt injection or poisoned inputs. The agent believes it is following its original instructions, but it has been redirected. AGT mitigates this through the Agent OS policy engine. Every agent action passes through a declarative policy evaluation layer before execution. The policy engine supports three modes: strict (deny by default), permissive (allow by default), and audit (log only). Unauthorized goal changes are blocked at the action layer, not at the prompt layer. from agent_os import StatelessKernel, ExecutionContext kernel = StatelessKernel() ctx = ExecutionContext(agent_id="my-agent", policies=["read_only"]) # This action is blocked by policy -- goal hijack prevented result = await kernel.execute( action="delete_database", params={"target": "production"}, context=ctx, ) # result.success = False, result.error = "Policy violation: read_only" The MCP Governance Proxy extends this to Model Context Protocol tool calls, evaluating policy before any tool invocation reaches the agent runtime. ASI-02: Tool Misuse & Exploitation The risk: An agent's authorized tools are abused in unintended ways, such as exfiltrating data via read operations or chaining benign tools into dangerous workflows. AGT provides capability-based security inspired by POSIX. Agents receive explicit capability grants (read, write, execute, network), not blanket tool access. The built-in strict mode blocks dangerous tools like run_shell, execute_command, and eval. Tool inputs are sanitized for command injection patterns and shell metacharacters. The verify_code_safety MCP tool checks generated code before execution, and tool allowlists/denylists give operators fine-grained control over which tools each agent can invoke. ASI-03: Identity & Privilege Abuse The risk: Agents escalate privileges by abusing identities or inheriting excessive credentials. Without proper identity, agents operate as ambient authority, and any compromise cascades. AgentMesh implements zero-trust identity using Decentralized Identifiers (DIDs). Every agent gets a cryptographic identity: did:agentmesh:{agentId}:{fingerprint} backed by Ed25519 key pairs. Trust is earned through a tiered model: Untrusted, Provisional, Trusted, Verified. Trust decays over time without positive signals, and delegation chains must always narrow scope (child capabilities must be a subset of parent capabilities). from agentmesh import AgentIdentity identity = AgentIdentity.create( name="data-analyst", sponsor="admin@contoso.com", capabilities=["read:data"], # Scoped -- cannot write or delete ) # Delegation MUST narrow, never widen child = identity.delegate( name="chart-helper", capabilities=["read:data:charts"], # Subset of parent ) ASI-04: Agentic Supply Chain Vulnerabilities The risk: Vulnerabilities in third-party tools, plugins, agent registries, or runtime dependencies that agents use to act, plan, or delegate. AgentMesh implements the AI-BOM (AI Bill of Materials), a comprehensive standard for tracking the full AI supply chain. This includes model provenance (base model ancestry, fine-tuning history, training cutoff dates), dataset tracking (training data, RAG sources, evaluation benchmarks with data cards including PII status, bias assessment, and consent tracking), weights versioning (SHA-256 hashes, quantization records, LoRA adapter metadata, SLSA build provenance), and software dependencies (SPDX-aligned package tracking with CI security scanning). # AI-BOM tracks the full supply chain ai_bom = { "modelProvenance": { "primary": {"provider": "anthropic", "model": "claude-3-sonnet"}, "fineTuning": {"method": "LoRA", "evaluationMetrics": {"accuracy": 0.94}}, }, "datasets": [ {"name": "FAQ KB", "type": "fine-tuning", "dataCard": {"piiStatus": "redacted"}}, {"name": "Product Docs", "type": "rag-source", "updateFrequency": "weekly"}, ], "weights": {"hash": "sha256:...", "format": "safetensors", "precision": "bf16"}, } ASI-05: Unexpected Code Execution The risk: Agents trigger remote code execution through tools, interpreters, or APIs. Without isolation, a single compromised tool call can escalate to full system access. Agent Runtime implements CPU ring-inspired execution isolation. Agents run in one of four execution rings: Ring 0 (root/supervisor), Ring 1 (privileged), Ring 2 (standard), and Ring 3 (sandbox/untrusted). Each ring has resource limits and the kill switch provides instant termination of runaway agents. from hypervisor.models import ( ActionDescriptor, ExecutionRing, ReversibilityLevel, ) from hypervisor.rings.enforcer import RingEnforcer from hypervisor.security.kill_switch import KillSwitch, KillReason # Define agent privilege levels AGENTS = { "supervisor": {"ring": ExecutionRing.RING_0_ROOT, "role": "Orchestrator"}, "data-agent": {"ring": ExecutionRing.RING_1_PRIVILEGED, "role": "Data Engineer"}, "analyst": {"ring": ExecutionRing.RING_2_STANDARD, "role": "Analyst"}, "user-bot": {"ring": ExecutionRing.RING_3_SANDBOX, "role": "User-Facing"}, } # Create a sandboxed action descriptor action = ActionDescriptor( name="run_query", required_ring=ExecutionRing.RING_2_STANDARD, reversibility=ReversibilityLevel.REVERSIBLE, ) # Enforce: sandbox agent cannot run a Ring 2 action enforcer = RingEnforcer() result = enforcer.check(agent_ring=ExecutionRing.RING_3_SANDBOX, action=action) # result.allowed = False -- ring violation prevented # Kill switch for runaway agents kill_switch = KillSwitch() kill_switch.terminate(agent_id="user-bot", reason=KillReason.RING_BREACH) ASI-06: Memory & Context Poisoning The risk: Persistent memory or long-running context is poisoned with malicious instructions. An attacker embeds hostile content in a document the agent later retrieves, causing it to follow injected goals. Agent OS provides a policy-controlled virtual filesystem (VFS) for agent memory. The VFS uses POSIX-style mount points: /mem/working for current context, /mem/episodic for past interactions, /mem/semantic for knowledge, /policy for read-only policy files, and /tools for tool interfaces. Each mount point has enforced permissions (read, write, execute, append). The policy directory is always read-only from user-space, preventing agents from modifying their own governance rules. from agent_control_plane.vfs import AgentVFS, MemoryBackend, FileMode # Create agent VFS with POSIX-style memory abstraction vfs = AgentVFS(agent_id="data-analyst") # Mount memory backends with explicit permissions vfs.mount("/mem/working", MemoryBackend(), mode=FileMode.READ | FileMode.WRITE) vfs.mount("/mem/semantic", MemoryBackend(), mode=FileMode.READ) # Read-only knowledge vfs.mount("/policy", MemoryBackend(), mode=FileMode.READ) # Policies always read-only # Agent can read working memory data = vfs.read("/mem/working/context.json") # Agent CANNOT write to policy -- enforced at VFS layer # vfs.write("/policy/rules.yaml", content) # Raises PermissionError # Agent CANNOT read semantic memory if not mounted # vfs.read("/mem/procedural/skills") # Raises FileNotFoundError The CMVK (Cross-Model Verification Kernel) adds a second layer: claims from agent context are verified across multiple AI models to detect poisoned content. Prompt injection patterns like 'ignore previous instructions' and 'disregard prior' are detected and blocked by the MCP proxy sanitizer before reaching the agent. ASI-07: Insecure Inter-Agent Communication The risk: Agents collaborate without adequate authentication, confidentiality, or validation. Messages between agents can be intercepted, forged, or replayed. AgentMesh provides IATP (Inter-Agent Trust Protocol) with E2E encrypted channels using the Signal protocol (X3DH key agreement + Double Ratchet). Every message gets per-message forward secrecy and post-compromise security. The EncryptedTrustBridge requires a successful trust handshake before any encrypted channel can be established, and mutual authentication via Ed25519 challenge-response ensures both parties prove identity at connection time. from agentmesh.encryption.bridge import EncryptedTrustBridge bridge = EncryptedTrustBridge(agent_did="did:mesh:alice", key_manager=keys) channel = await bridge.open_secure_channel("did:mesh:bob", bob_bundle) ciphertext = channel.send(b"governed action") # E2E encrypted ASI-08: Cascading Agent Failures The risk: An initial error or compromise triggers multi-step compound failures across chained agents. One agent's failure propagates through the entire system. Agent SRE brings production-grade reliability engineering to agent fleets. Circuit breakers automatically isolate failing agents before failures cascade. SLO enforcement with error budgets provides quantified failure tolerance that triggers automatic intervention. Cascading failure detection monitors dependency chains for propagation patterns, and canary deploys enable gradual rollout of agent changes to detect issues early. OpenTelemetry integration provides distributed tracing across multi-agent workflows. The key insight: treat AI agents like microservices. Apply the same SRE discipline (SLOs, error budgets, circuit breakers, chaos testing) that keeps cloud infrastructure reliable. ASI-09: Human-Agent Trust Exploitation The risk: Attackers leverage misplaced user trust in agents' autonomy to authorize dangerous actions. Users rubber-stamp agent requests because they trust the agent, and attackers exploit this approval fatigue. Agent OS implements approval workflows that require explicit human confirmation for high-risk actions. The system supports configurable risk assessment (critical, high, medium, low), quorum logic for critical actions requiring multiple approvals, and expiration tracking to prevent stale authorizations. The escalation handler includes fatigue detection: if an agent floods reviewers with escalation requests, subsequent requests are auto-denied to prevent the approval-fatigue attack. from agent_os.integrations.escalation import ( EscalationHandler, InMemoryApprovalQueue, DefaultTimeoutAction, QuorumConfig, ) # Configure approval workflow with fatigue protection handler = EscalationHandler( backend=InMemoryApprovalQueue(), timeout_seconds=300, # 5-minute approval window default_action=DefaultTimeoutAction.DENY, # Deny if no human responds quorum=QuorumConfig(required=2, total=3), # 2-of-3 approvers for critical fatigue_threshold=5, # Auto-deny after 5 rapid requests fatigue_window_seconds=60, # Within a 60-second window ) # Three-outcome model: allow, deny, or escalate # High-risk actions trigger escalation to human reviewers # If the agent triggers too many escalations, fatigue detection kicks in ASI-10: Rogue Agents The risk: Agents operating outside their defined scope through configuration drift, reprogramming, or emergent misbehavior. A rogue agent might gradually expand its actions beyond its mandate without any single action triggering a block. AGT combines runtime behavioral monitoring with instant kill capability. Ring isolation confines rogue agents to their execution ring, preventing privilege escalation. The kill switch provides immediate termination for agents exhibiting rogue behavior (behavioral drift, rate limit violations, ring breaches). Trust score decay tracks agent behavior over time, and the Merkle audit chain provides tamper-evident, cryptographic proof of every agent action. from agentmesh.governance.audit import AuditEntry, MerkleAuditChain from hypervisor.security.kill_switch import KillSwitch, KillReason # Tamper-evident audit trail chain = MerkleAuditChain() entry = AuditEntry( event_type="tool_call", agent_did="did:agentmesh:data-bot:abc123", action="query_database", outcome="allowed", policy_decision="permit", matched_rule="read_only_policy", ) chain.add_entry(entry) # Auto-computes hash chain # Verify integrity -- any tampering breaks the chain proof = chain.get_proof(entry.entry_id) assert chain.verify_proof(proof) # Cryptographic verification # Kill switch for rogue behavior kill = KillSwitch() kill.terminate( agent_id="data-bot", reason=KillReason.BEHAVIORAL_DRIFT, # Also: RATE_LIMIT, RING_BREACH, MANUAL ) Cross-Cutting Principle: Least Agency The Least Agency principle is emphasized throughout the OWASP Agentic Top 10 as a foundational design principle. Agents should be granted the minimum capabilities, permissions, and autonomy necessary to complete their assigned tasks. Layer Least Agency Mechanism Agent OS Policy engine enforces deny-by-default; agents must be explicitly granted each capability AgentMesh DID identity with scoped capabilities; delegation requires narrowing (child <= parent) Agent Runtime Execution rings (Ring 0-3) enforce privilege tiers; untrusted agents run in Ring 3 Agent SRE Resource limits and error budgets cap agent impact radius Performance: Governance Without Latency Tax A common concern with runtime governance is performance overhead. AGT's benchmarks demonstrate that policy enforcement adds negligible latency: Metric Value Single rule evaluation 84,000 ops/sec 1000 concurrent agents 47,000 ops/sec Policy evaluation latency <0.1ms (p99) Prompt-based violation rate 26.67% AGT policy violation rate 0.00% Conformance tests 992 Architecture Decision Records 25 The key takeaway: deterministic policy enforcement is orders of magnitude more reliable than prompt-based guardrails, and it runs fast enough for real-time agent workloads. Framework Integrations AGT is framework-agnostic. SDKs are available in Python, TypeScript, .NET, Rust, and Go. Native integrations exist for: LangChain and LangGraph CrewAI AutoGen (Microsoft) Semantic Kernel (Microsoft) OpenAI Agents SDK PydanticAI Model Context Protocol (MCP) Agent-to-Agent Protocol (A2A) Each integration wraps the agent framework's tool-calling and message-passing interfaces with AGT's policy engine, trust scoring, and audit logging. Adding governance to an existing agent takes minutes, not weeks. Compliance Framework Alignment Framework AGT Coverage OWASP Agentic Top 10 (2026) All 10 risk categories mapped NIST AI RMF Govern, Map, Measure, Manage functions addressed EU AI Act Risk classification, audit trails, human oversight SOC 2 Type II Audit logging, access controls, change management CSA ATF Zero-trust agent architecture alignment Singapore MGF Zero-trust, accountability, oversight layers Getting Started # Install the complete governance stack pip install agent-governance-toolkit[full] # Or install individual components pip install agent-os-kernel # Policy engine, VFS, approval workflows pip install agentmesh-platform # Identity, trust, encryption, audit pip install agentmesh-runtime # Execution rings, kill switch, saga pip install agent-sre # Circuit breakers, SLOs, chaos testing The quickstart tutorial walks through adding policy enforcement to an existing LangChain agent in under 10 minutes. Start with a single policy rule and expand as your governance requirements grow. Contribute and Collaborate AGT is open source under the MIT license. The project has over 2,000 GitHub stars and contributors from 40+ countries. Whether you are building agent governance for your enterprise, integrating a new framework, or extending the policy engine with OPA/Rego or Cedar policies, we welcome contributions. Repository: https://github.com/microsoft/agent-governance-toolkit Documentation: https://microsoft.github.io/agent-governance-toolkit Discussions: GitHub Discussions on the repository Disclaimer: This document is provided for informational purposes. Code examples are from the public AGT repository and may evolve. Always refer to the latest repository documentation for current APIs.
