Planning your move to Microsoft Defender portal for all Microsoft Sentinel customers
In November 2023, Microsoft announced our strategy to unify security operations by bringing the best of XDR and SIEM together. Our first step was bringing Microsoft Sentinel into the Microsoft Defender portal, giving teams a single, comprehensive view of incidents, reducing queue management, enriching threat intel, streamlining response and enabling SOC teams to take advantage of Gen AI in their day-to-day workflow. Since then, considerable progress has been made with thousands of customers using this new unified experience; to enhance the value customers gain when using Sentinel in the Defender portal, multi-tenancy and multi-workspace support was added to help customers with more sophisticated deployments. Our mission is to unify security operations by bringing all your data, workflows, and people together to unlock new capabilities and drive better security outcomes. As a strong example of this, last year we added extended posture management, delivering powerful posture insights to the SOC team. This integration helps build a closed-loop feedback system between your pre- and post-breach efforts. Exposure Management is just one example. By bringing everything together, we can take full advantage of AI and automation to shift from a reactive to predictive SOC that anticipates threats and proactively takes action to defend against them. Beyond Exposure Management, Microsoft has been constantly innovating in the Defender experience, adding not just SIEM but also Security Copilot. The Sentinel experience within the Defender portal is the focus of our innovation energy and where we will continue to add advanced Sentinel capabilities going forward. Onboarding to the new unified experience is easy and doesn’t require a typical migration. Just a few clicks and permissions. Customers can continue to use Sentinel in the Azure portal while it is available even after choosing to transition. Today, we’re announcing that we are moving to the next phase of the transition with a target to retire the Azure portal for Microsoft Sentinel by July 1, 2026. Customers not yet using the Defender portal should plan their transition accordingly. “Really amazing to see that coming, because cross querying with tables in one UI is really cool! Amazing, big step forward to the unified [Defender] portal.” Glueckkanja AG “The biggest benefit of a unified security operations solution (Microsoft Sentinel + Microsoft Defender XDR) has been the ability to combine data in Defender XDR with logs from third party security tools. Another advantage developed has been to eliminate the need to switch between Defender XDR and Microsoft Sentinel portals, now having a single pane of glass, which the team has been wanting for some years.” Robel Kidane, Group Information Security Manager, Renishaw PLC Delivering the SOC of the future Unifying threat protection, exposure management and security analytics capabilities in one pane of glass not only streamlines the user experience, but also enables Sentinel customers to realize security outcomes more efficiently: Analyst efficiency: A single portal reduces context switching, simplifies workflows, reduces training overhead, and improves team agility. Integrated insights: SOC-focused case management, threat intelligence, incident correlation, advanced hunting, exposure management, and a prioritized incident queue enriched with business and sensitivity context—enabling faster, more informed detection and response across all products. SOC optimization: Security controls that can be adjusted as threats and business priorities change to control costs and provide better coverage and utilization of data, thus maximizing ROI from the SIEM. Accelerated response: AI-driven detection and response which reduces mean time to respond (MTTR) by 30%, increases security response efficiency by 60%, and enables embedded Gen AI and agentic workflows. What’s next: Preparing for the retirement of the Sentinel Experience in the Azure Portal Microsoft is committed to supporting every single customer in making that transition over the next 12 months. Beginning July 1, 2026, Sentinel users will be automatically redirected to the Defender portal. After helping thousands of customers smoothly make the transition, we recommend that security teams begin planning their migration and change management now to ensure continuity and avoid disruption. While the technical process is very straightforward, we have found that early preparation allows time for workflow validation, training, and process alignment to take full advantage of the new capabilities and experience. Tips for a Successful Migration to Microsoft Defender 1. Leverage Microsoft’s help: Leverage Microsoft documentation, instructional videos, guidance, and in-product support to help you be successful. A good starting point is the documentation on Microsoft Learn. 2. Plan early: Engage stakeholders early including SOC and IT Security leads, MSSPs, and compliance teams to align on timing, training and organizational needs. Make sure you have an actionable timeline and agreement in the organization around when you can prioritize this transition to ensure access to the full potential of the new experience. 3. Prepare your environment: Plan and design your environment thoroughly. This includes understanding the prerequisites for onboarding Microsoft Sentinel workspaces, reviewing and deciding on access controls, and planning the architecture of your tenant and workspace. Proper planning will ensure a smooth transition and help avoid any disruptions to your security operations. 4. Leverage Advanced Threat Detection: The Defender portal offers enhanced threat detection capabilities with advanced AI and machine learning for Microsoft Sentinel. Make sure to leverage these features for faster and more accurate threat detection and response. This will help you identify and address critical threats promptly, improving your overall security posture. 5. Utilize Unified Hunting and Incident Management: Take advantage of the enhanced hunting, incident, and investigation capabilities in Microsoft Defender. This provides a comprehensive view for more efficient threat detection and response. By consolidating all security incidents, alerts, and investigations into a single unified interface, you can streamline your operations and improve efficiency. 6. Optimize Cost and Data Management The Defender portal offers cost and data optimization features, such as SOC Optimization and Summary Rules. Make sure to utilize these features to optimize your data management, reduce costs, and increase coverage and SIEM ROI. This will help you manage your security operations more effectively and efficiently. Unleash the full potential of your Security team The unified SecOps experience available in the Defender portal is designed to support the evolving needs of modern SOCs. The Defender portal is not just a new home for Microsoft Sentinel - it’s a foundation for integrated, AI-driven security operations. We’re committed to helping you make this transition smoothly and confidently. If you haven’t already joined the thousands of security organizations that have done so, now is the time to begin. Resources AI-Powered Security Operations Platform | Microsoft Security Microsoft Sentinel in the Microsoft Defender portal | Microsoft Learn Shifting your Microsoft Sentinel Environment to the Defender Portal | Microsoft Learn Microsoft Sentinel is now in Defender | YouTubeSensitivity Auto-labelling via Document Property
Why is this needed? Sensitivity labels are generally relevant within an organisation only. If a file is labelled within one environment and then moved to another environment, sensitivity label content markings may be visible, but by default, the applied sensitivity label will not be understood. This can lead to scenarios where information that has been generated externally is not adequately protected. My favourite analogy for these scenarios is to consider the parallels between receiving sensitive information and unpacking groceries. When unpacking groceries, you might sit your grocery bag on a counter or on the floor next to the pantry. You’ll likely then unpack each item, take a look at it and then decide where to place it. Without looking at an item to determine its correct location, you might place it in the wrong location. Porridge might be safe from the kids on the bottom shelf. If you place items that need to be protected, such as chocolate, on the bottom shelf, it’s not likely to last very long. So, I affectionately refer to information that hasn’t been evaluated as ‘porridge’, as until it has been checked, it will end up on the bottom shelf of the pantry where it is quite accessible. Label-based security controls, such as Data Loss Prevention (DLP) policies using conditions of ‘content contains sensitivity label’ will not apply to these items. To ensure the security of any contained sensitive information, we should look for potential clues to its sensitivity and then utilize these clues to ensure that the contained information is adequately protected - We take a closer look at the ‘porridge’, determine whether it’s an item that needs protection and if so, move it to a higher shelf in the pantry so that it’s out of reach for the kids. Effective use of Purview revolves around the use of ‘know your data’ strategies. We should be using as many methods as possible to try to determine the sensitivity of items. This can include the use of Sensitive Information Types (SITs) containing keyword or pattern-based classifiers, trainable classifiers, Exact Data Match, Document fingerprinting, etc. Matching items via SITs present in the items content can be problematic due to false positives. Keywords like ‘Sensitive’ or ‘Protected’ may be mentioned out of context, such as when referring to a classification or an environment. When classifications have been stamped via a property, it allows us to match via context rather than content. We don’t need to guess at an item’s sensitivity if another system has already established what the item’s classification is. These methods are much less prone to false positives. Why isn’t everyone doing this? Document properties are often not considered in Purview deployments. SharePoint metadata management seems to be a dying artform and most compliance or security resources completing Purview configurations don’t have this skill set. There’s also a lack of understanding of the relevance of checking for item properties. Microsoft haven’t helped as the documentation in this space is somewhat lacking and needs to be unpicked via some aligning DLP guidance (Create a DLP policy to protect documents with FCI or other properties). Many of these configurations will also be tied to regional requirements. Document properties being used by systems where I’m from, in Australia, will likely be very different to those used in other parts of the world. In the following sections, we’ll take a look at applicable use cases and walk through how to enable these configurations. Scenarios for use Labelling via document property isn’t for everyone. If your organisation is new to classification or you don’t have external partners that you collaborate with at higher sensitivity levels, then this likely isn’t for you. For those that collaborate heavily and have a shared classification framework, as is often seen across government, this is a must! This approach will also be highly relevant to multi-tenant organisations or conglomerates where information is regularly shared between environments. The following scenarios are examples of where this configuration will be relevant: 1. Migrating from 3 rd party classification tools If an item has been previously stamped by a 3 rd party classification tool, then evaluating its applied document properties will provide a clear picture of its security classification. These properties can then be used in service-based auto-labelling policies to effectively transition items from 3 rd party tools to Microsoft Purview sensitivity labels. As labels are applied to items, they will be brought into scope of label-based controls. 2. Detecting data spill Data spill is a term that is used to define situations where information that is of a higher than permitted security classification land in an environment. Consider a Microsoft 365 tenant that is approved for the storage of Official information but Top Secret files are uploaded to it. Document properties that align with higher than permitted classifications provide us with an almost guaranteed method of identifying spilled items. Pairing this document property with an auto-labelling policy allows for the application of encryption to lock unauthorized users out of the items. Tools like Content Explorer and eDiscovery can then be used to easily perform cleanup activities. If using document properties and auto-labelling for this purpose, keep in mind that you’ll need to create sensitivity labels for higher than permitted classifications in order to catch spilled items. These labels won’t impact usability as you won’t publish them to users. You will, however, need to publish them to a single user or break glass account so that they’re not ignored by auto-labelling. 3. Blocking access by AI tools If your organization was concerned about items with certain properties applied being accessed by generative AI tools, such as Copilot, you could use Auto-labelling to apply a sensitivity label that restricts EXTRACT permissions. You can find some information on this at Microsoft 365 Copilot data protection architecture | Microsoft Learn. This should be relevant for spilled data, but might also be useful in situations where there are certain records that have been marked via properties and which should not be Copilot accessible. 4. External Microsoft Purview Configurations Sensitivity labels are relevant internally only. A label, in its raw form, is essentially a piece of metadata with an ID (or GUID) that we stamp on pieces of information. These GUIDs are understood by your tenant only. If an item marked with a GUID shows up in another Microsoft 365 tenant, the GUID won’t correspond with any of that tenant’s labels or label-based controls. The art in Microsoft Purview lies in interpreting the sensitivity of items based on content markings and other identifiers, so that data security can be maintained. Document properties applied by Purview, such as ClassificationContentMarkingHeaderText are not relevant to a specific tenant, which makes them portable. We can use these properties to help maintain classifications as items move between environments. 5. Utilizing metadata applied by Records Management solutions Some EDRMS, Records or Content Management solutions will apply properties to items. If an item has been previously managed and then stamped with properties, potentially including a security classification, via one of these systems, we could use this information to inform sensitivity label application. 6. 3 rd party classification tools used externally Even if your organisation hasn’t been using 3rd party classification tools, you should consider that partner organisations, such as other Government departments, might be. Evaluating the properties applied by external organisations to items that you receive will allow you to extend protections to these items. If classification tools like Janus or Titus are used in your geography/industry, then you may want to consider checking for their properties. Regarding the use of auto-classification tools Some organisations, particularly those in Government, will have organisational policies that prevent the use of automatic classification capabilities. These policies are intended to ensure that each item is assessed by an actual person for risk of disclosure rather than via an automated service that could be prone to error. However, when auto-labelling is used to interpret and honour existing classifications, we are lowering rather than raising the risk profile. If the item’s existing classification (applied via property) is ignored, the item will be treated as porridge and is likely to be at risk. If auto-labelling is able to identify a high-risk item and apply the relevant label, it will then be within scope of Purview’s data security controls, including label-based DLP, groups and sites data out of place alerting, and potentially even item encryption. The outcome is that, through the use of auto-labelling, we are able to significantly reduce risk of inappropriate or unintended disclosure. Configuration Process Setting up document property-based auto-labelling is fairly straightforward. We need to setup a managed property and then utilize it an auto-labelling policy. Below, I've split this process into 6 steps: Step 1 – Prepare your files In order to make use of document properties, an item with the properties applied will first need to be indexed by SharePoint. SharePoint will record the properties as ‘crawled properties’, which we’ll then need to convert into ‘managed properties’ to make them useful. If you already have items with the relevant properties stored in SharePoint, then they are likely already indexed. If not, you’ll need to upload or create an item or items with the properties applied. For testing, you’ll want to create a file with each property/value combination so that you can confirm that your auto-labelling policies are all working correctly. This could require quite a few files depending on the number of properties you’re looking for. To kick off your crawled property generation though, you could create or upload a single file with the correct properties applied. For example: In the above, I’ve created properties for ClassificationContentMarkingHeaderText and ClassificationContentMarkingFooterText, which you’ll often see applied by Purview when an item has a sensitivity label content marking applied to it. I’ve also included properties to help identify items classified via JanusSeal, Titus and Objective. Step 2 – Index the files After creating or uploading your file, we then need SharePoint to index it. This should happen fairly quickly depending on the size of your environment. I'd expect to wait sometime between 10 minutes and 24 hrs. If you're not in a hurry, then I'd recommend just checking back the next day. You'll know when this has been completed when you head into SharePoint Admin > Search > Managed Search Schema > Crawled Properties and can find your newly indexed properties: Step 3 – Configure managed properties Next, the properties need to be configured as managed properties. To do this, go to SharePoint Admin > More features > Search > Managed Search Schema > Managed Properties. Create a new managed property and give it a name. Note that there are some character restrictions in naming, but you should be able to get it close to your document property name. Set the property’s type to text, select queryable and retrievable. Under ‘mappings to crawled properties’, choose add mapping, search for and select the property indexed from the file property. Note that the crawled property will have the same name as your document property, so there’s no need to browse through all of them: Repeat this so that you have a managed property for each document property that you want to look for. Step 4 – Configure Auto-labelling policies Next up, create some auto-labelling policies. You’ll need one for each label that you want to apply, not one per property as you can check multiple properties within the one auto-labelling policy. - From within Purview, head to Information Protection > Policies > Auto-labelling policies. - Create a new policy using the custom policy template. - Give your policy an appropriate name (e.g. Label PROTECTED via property). - Select the label that you want to apply (e.g. PROTECTED). - Select SharePoint based services (SharePoint and OneDrive). - Name your auto-labelling rules appropriately (e.g. SPO – Contains PROTECTED property) - Enter your conditions as a long string with property and value separated via a colon and multiple entries separated with a comma. For example: ClassificationContentMarkingHeaderText:PROTECTED,ClassificationContentMarkingFooterText:PROTECTED,Objective-Classification:PROTECTED,PMDisplay:PROTECTED,TitusSEC:PROTECTED Note that the properties that you are referencing are the Managed Property rather than the document property. This will be relevant if your managed property ended up having a different name due to character restrictions. After pasting in your string into the UI, the resultant rule should look something like this: When done, you can either leave your policy in simulation mode or save it and then turn it on from the auto-labelling policies screen. Just be aware of any potential impacts, such as accidently locking users out by automatically deploying a label with encryption configuration. You can reduce any potential impact by targeting your auto-labelling policy at a site or set of sites initially and then expanding its scope after testing. Step 5 - Test Testing your configuration will be as easy as uploading or creating a set of files with the relevant document properties in place. Once uploaded, you’ll need to give SharePoint some time to index the items and then the auto-labelling policy some time to apply sensitivity labels to them. To confirm label application, you can head to the document library where your test files are located and enable the sensitivity column. Files that have been auto-labelled will have their label listed: You could also check for auto-labelling activity in Purview via Activity explorer: Step 6 – Expand into DLP If you’ve spent the time setting up managed properties, then you really should consider capitalizing on them in your DLP configurations. DLP policy conditions can be configured in the same manner that we configured Auto-labelling in Step 3 above. The document property also gives us an anchor for DLP conditions that is independent of an item’s sensitivity label. You may wish to consider the following: DLP policies blocking external sharing of items with certain properties applied. This might be handy for situations where auto-labelling hasn’t yet labelled an item. DLP policies blocking the external sharing of items where the applied sensitivity label doesn’t match the applied document property. This could provide an indication of risky label downgrade. You could extend such policies into Insider Risk Management (IRM) by creating IRM policies that are aligned with the above DLP policies. This will allow for document properties to be considered in user risk calculation, which can inform controls like Adaptive Protection. Here's an example of a policy from the DLP rule summary screen that shows conditions of item contains a label or one of our configured document properties: Thanks for reading and I hope this article has been of use. If you have any questions or feedback, please feel free to reach out.Step by Step: 2-Tier PKI Lab
Purpose of this blog Public Key Infrastructure (PKI) is the backbone of secure digital identity management, enabling encryption, digital signatures, and certificate-based authentication. However, neither setting up a PKI nor management of certificates is something most IT pros do on a regular basis and given the complexity and vastness of the subject it only makes sense to revisit the topic from time to time. What I have found works best for me is to just set up a lab and get my hands dirty with the topic that I want to revisit. One such topic that I keep coming back to is PKI - be it for creating certificate templates, enrolling clients, or flat out creating a new PKI itself. But every time I start deploying a lab or start planning a PKI setup, I end up spending too much time sifting through the documentations and trying to figure out why my issuing certificate authority won't come online! To make my life easier I decided to create a cheatsheet to deploy a simple but secure 2-tier PKI lab based on industry best practices that I thought would be beneficial for others like me, so I decided to polish it and make it into a blog. This blog walks through deploying a two-tier PKI hierarchy using Active Directory Certificate Services (AD CS) on Windows Server: an offline Root Certification Authority (Root CA) and an online Issuing Certification Authority (Issuing CA). We’ll cover step-by-step deployment and best practices for securing the root CA, conducting key ceremonies, and maintaining Certificate Revocation Lists (CRLs). Overview: Two-Tier PKI Architecture and Components In a two-tier PKI, the Root CA sits at the top of the trust hierarchy and issues a certificate only to the subordinate Issuing CA. The Root CA is kept offline (disconnected from networks) to protect its private key and is typically a standalone CA (not domain-joined). The Issuing CA (sometimes called a subordinate or intermediate CA) is kept online to issue certificates to end-entities (users, computers, services) and is usually an enterprise CA integrated with Active Directory for automation and certificate template support. Key components: Offline Root CA: A standalone CA, often on a workgroup server, powered on only when necessary (initial setup, subordinate CA certificate signing, or periodic CRL publishing). By staying offline, it is insulated from network threats. Its self-signed certificate serves as the trust anchor for the entire PKI. The Root CA’s private key must be rigorously protected (ideally by a Hardware Security Module) because if the root is compromised, all certificates in the hierarchy are compromised. Online Issuing CA: An enterprise subordinate CA (domain-joined) that handles day-to-day certificate issuance for the organization. It trusts the Root CA (via the root’s certificate) and is the one actually responding to certificate requests. Being online, it must also be secured, but its key is kept online for operations. Typically, the Issuing CA publishes certificates and CRLs to Active Directory and/or HTTP locations for clients to download. The following diagram shows the simplified view of this implementations: The table below summarizes the roles and differences: Aspect Offline Root CA Online Issuing CA Role Standalone Root CA (workgroup) Enterprise Subordinate CA (domain member) Network Connectivity Kept offline (powered off or disconnected when not issuing) Online (running continuously to serve requests) Usage Signs only one certificate (the subordinate CA’s cert) and CRLs Issues end-entity certificates (users, computers, services) Active Directory Not a member of AD domain; doesn’t use templates or auto-enrollment Integrated with AD DS; uses certificate templates for streamlined issuance Security Extremely high: physically secured, limited access, often protected by HSM Very High: server hardened, but accessible on network; HSM recommended for private key CRL Publication Manual. Admin must periodically connect, generate, and distribute CRL. Delta CRLs usually disabled. Automatic. Publishes CRLs to configured CDP locations (AD DS, HTTP) at scheduled intervals. Validity Period Longer (e.g. 5-10+ years for the CA certificate) to reduce frequency of renewal. Shorter (e.g. 2 years) to align with organizational policy; renewed under the root when needed. In this lab setup, we will create a Contoso Root CA (offline) and a Contoso Issuing CA (online) as an example. This mirrors real-world best practices which is to "deploy a standalone offline root CA and an online enterprise subordinate CA”. Deploying the Offline Root CA Setting up the offline Root CA involves preparing a dedicated server, installing AD CS, configuring it as a root CA, and then securing it. We’ll also configure certificate CDP/AIA (CRL Distribution Point and Authority Information Access) locations so that issued certificates will point clients to the correct locations to fetch the CA’s certificate and revocation list. Step 1: Prepare the Root CA Server (Offline) Provision an isolated server: Install a Windows Server OS (e.g., Windows Server 2022) on the machine designated to be the Root CA. Preferably on a portable enterprise grade physical server that can be stored in a safe. Do not join this server to any domain – it should function in a Workgroup to remain independent of your AD forest. System configuration: Give the server a descriptive name (e.g., ROOTCA) and assign a static IP (even though it will be offline, a static IP helps when connecting it temporarily for management). Install the latest updates and security patches while it’s still able to go online. Lock down network access: Once setup is complete, disable or unplug network connections. If the server must remain powered on for any reason, ensure all unnecessary services/ports are disabled to minimize exposure. In practice, you will keep this server shut down or physically disconnected except when performing CA maintenance. Step 2: Install the AD CS Role on the Root CA Add the Certification Authority role: On the Root CA server, open Server Manager and add the Active Directory Certificate Services role. During the wizard, select the Certification Authority role service (no need for web enrollment or others on the root). Proceed through the wizard and complete the installation. You can also install the CA role and management tools via PowerShell: Install-WindowsFeature AD-Certificate -IncludeManagementToolsThis Role Services: Choose Certification Authority. Setup Type: Select Standalone CA (since this root CA is not domain-joined). CA Type: Select Root CA. Private Key: Choose “Create a new private key.” Cryptography: If using an HSM, select the HSM’s Cryptographic Service Provider (CSP) here; otherwise use default. Choose a strong key length (e.g., 2048 or 4096 bits) and a secure hash algorithm (SHA-256 or higher). CA Name: Provide a common name for the CA (e.g., “Contoso Root CA”). This name will appear in issued certificates as the Issuer. Avoid using a machine DNS name here for security – pick a name without revealing the server’s actual hostname. Validity Period: Set a long validity (e.g., 10 years) for the root CA’s self-signed certificate. A decade is common for enterprise roots, reducing how often you must touch the offline CA for renewal. Database: Specify locations for the CA database and logs (the defaults are fine for a lab). Review settings and complete the configuration. This process will generate the root CA’s key pair and self-signed certificate, establishing the Root CA.Post-install configuration: After the binary installation, click Configure Active Directory Certificate Services (a notification in Server Manager). In the configuration wizard: You can also perform this configuration via PowerShell in one line: Install-AdcsCertificationAuthority ` -CAType StandaloneRootCA ` -CryptoProviderName "YourHSMProvider" ` -HashAlgorithmName SHA256 -KeyLength 2048 ` -CACommonName "Contoso Root CA" ` -ValidityPeriod Years -ValidityPeriodUnits 10 This would set up a standalone Root CA named "Contoso Root CA" with a 2048-bit key on an HSM provider, valid for 10 years. Step 3: Integrate an HSM (Optional but Recommended) If your lab has a Hardware Security Module, use it to secure the Root CA’s keys. Using an HSM provides a dedicated, tamper-resistant storage for CA private keys and can further protect against key compromise. To integrate: Install the HSM vendor’s software and drivers on the Root CA server. Initialize the HSM and create a security world or partition as per the vendor instructions. Before or during the CA configuration (Step 2 above), ensure the HSM is ready to generate/store the key. When running the AD CS configuration, select the HSM’s CSP/KSP for the cryptographic provider so that the CA’s private key is generated on the HSM. Secure any HSM admin tokens or smartcards. For a root CA, you might employ M of N key splits – requiring multiple key custodians to collaborate to activate the HSM or key – as part of the key ceremony (discussed later). (If an HSM is not available, the root key will be stored on the server’s disk. At minimum, protect it with a strong admin passphrase when prompted, and consider enabling the option to require administrator interaction (e.g., a password) whenever the key is accessed.) Step 4: Configure CA Extensions (CDP/AIA) It’s critical to configure how the Root CA publishes its certificate and revocation list, since the root is offline and cannot use Active Directory auto-publishing. Open the Certification Authority management console (certsrv.msc), right-click the CA name > Properties, and go to the Extensions tab. We will set the CRL Distribution Points (CDP) and Authority Information Access (AIA) URLs: CRL Distribution Point (CDP): This is where certificates will tell clients to fetch the CRL for the Root CA. By default, a standalone CA might have a file:// path or no HTTP URL. Click Add and specify an HTTP URL that will be accessible to all network clients, such as: http://<IssuingCA_Server>/CertEnroll/<CaName><CRLNameSuffix><DeltaCRLAllowed>.crl For example, if your issuing CA’s server name is ISSUINGCA.contoso.local, the URL might be http://issuingca.contoso.local/CertEnroll/Contoso%20Root%20CA.crl This assumes the Issuing CA (or another web server) will host the Root CA’s CRL in the CertEnroll directory. Check the boxes for “Include in the CDP extension of issued certificates” and “Include in all CRLs. Clients use this to find Delta CRLs” (you can uncheck the delta CRL publication on the root, as we won’t use delta CRLs on an offline root). Since the root CA won’t often revoke its single issued cert (the subordinate CA), delta CRLs aren’t necessary. Note: If your Active Directory is in use and you want to publish the Root CA’s CRL to AD, you can also add an ldap:///CN=... path and check “Publish in Active Directory”. However, publishing to AD from an offline CA must be done manually using the following command when the root is temporarily connected. certutil -dspublish Many setups skip LDAP for offline roots and rely on HTTP distribution. Authority Information Access (AIA): This is where the Root CA’s certificate will be published for clients to download (to build certificate chains). Add an HTTP URL similarly, for example: http://<IssuingCA_Server>/CertEnroll/<ServerDNSName>_<CaName><CertificateName>.crt This would point to a copy of the Root CA’s certificate that will be hosted on the issuing CA web server. Check “Include in the AIA extension of issued certificates”. This way, any certificate signed by the Root CA (like your subordinate CA’s cert) contains a URL where clients can fetch the Root CA’s cert if they don’t already have it. After adding these, remove any default entries that are not applicable (e.g., LDAP if the root isn’t going to publish to AD, or file paths that won’t be used by clients). These settings ensure that certificates issued by the Root CA (in practice, just the subordinate CA’s certificate) will carry the correct URLs for chain building and revocation checking. Step 5: Back Up the Root CA and Issue the Subordinate Certificate With the Root CA configured, we need to issue a certificate for the Issuing CA (subordinate). We’ll perform that in the next section from the Issuing CA’s side via a request file. Before taking the root offline, ensure you: Back up the CA’s private key and certificate: In the Certification Authority console, or via the CA Backup wizard, export the Root CA’s key pair and CA certificate. Protect this backup (store it offline in a secure location, e.g., on encrypted removable media in a safe). This backup is crucial for disaster recovery or if the Root CA needs to be migrated or restored. Save the Root CA Certificate: You will need the Root CA’s public certificate (*.crt) to distribute to other systems. Have it exported (Base-64 or DER format) for use on the Issuing CA and for clients. Initial CRL publication: Manually publish the first CRL so that it can be distributed. Open an elevated Command Prompt on the Root CA and run: certutil -crl This generates a new CRL file (in the CA’s configured CRL folder, typically %windir%\system32\CertSrv\CertEnroll). Take that CRL file and copy it to the designated distribution point (for example, to the CertEnroll directory on the Issuing CA’s web server, as per the HTTP URL configured). If using Active Directory for CRL distribution, you would also publish it to AD now (e.g., certutil -dspublish -f RootCA.crl on a domain-connected machine). In most lab setups, copying to an HTTP share is sufficient. With these tasks done, the Root CA is ready. At this point, disconnect or power off the Root CA and store it securely – it should remain offline except when it’s absolutely needed (like publishing a new CRL or renewing the subordinate CA’s certificate in the far future). Keeping the root CA offline maximizes its security by minimizing exposure to compromise. Best Practices for Securing the Root CA: The Root CA is the trust anchor, so apply stringent security practices: Physical security: Store the Root CA machine in a locked, secure location. If it’s a virtual machine, consider storing it on a disconnected hypervisor or a USB drive locked in a safe. Only authorized PKI team members should have access. An offline CA should be treated like crown jewels – offline CAs should be stored in secure locations. Minimal exposure: Keep the Root CA powered off and disconnected when not in use. It should not be left running or connected to any network. Routine operations (like issuing end-entity certs) should never involve the root. Admin access control: Limit administrative access on the Root CA server. Use dedicated accounts for PKI administration. Enable auditing on the CA for any changes or issuance events. No additional roles or software: Do not use the Root CA server for any other function (no web browsing, no email, etc.). Fewer installed components means fewer potential vulnerabilities. Protect the private key: Use an HSM if possible; if not, ensure the key is at least protected by a strong password and consider splitting knowledge of that password among multiple people (so no single person can activate the CA). Many organizations opt for an offline root key ceremony (see below) to generate and handle the root key with multiple witnesses and strict procedures. Keep system time and settings consistent: If the Root CA is powered off for long periods, ensure its clock is accurate whenever it is started (to avoid issuing a CRL or certificate with a wrong date). Don’t change the server name or CA name after installation (doing so invalidates issued certs). Periodic health checks: Even though offline, plan to turn on the Root CA at a secure interval (e.g., semi-annually or annually) to perform tasks like CRL publishing and system updates. Make sure to apply OS security updates during these maintenance windows, as offline does not mean immune to vulnerabilities (especially if it ever connects to a network for CRL publication or uses removable media). Deploying the Online Issuing CA Next, set up the Issuing CA server which will actually issue certificates to end entities in the lab. This server will be domain-joined (if using AD integration) and will obtain its CA certificate from the Root CA we just configured. Step 1: Prepare the Issuing CA Server Provision the server: Install Windows Server on a new machine (or VM) that will be the Issuing CA. Join this server to the Active Directory domain (e.g., Contoso.local). Being an enterprise CA, it needs domain membership to publish templates and integrate with AD security groups. Rename the server to something descriptive like ISSUINGCA for clarity. Assign a static IP and ensure it can communicate on the network. IIS for web enrollment (optional): If you plan to use the Web Enrollment or Certificate Enrollment Web Services, ensure IIS is installed. (The AD CS installation wizard can add it if you include those role services.) For this guide, we will include the Web Enrollment role so that the CertEnroll directory is set up for hosting certificate and CRL files. Step 2: Install AD CS Role on Issuing CA On the Issuing CA server, add the Active Directory Certificate Services role via Server Manager or PowerShell. This time, select both Certification Authority and Certification Authority Web Enrollment role services (Web Enrollment will set up the HTTP endpoints for certificate requests if needed). For example, using PowerShell: Install-WindowsFeature AD-Certificate, ADCS-Web-Enrollment -IncludeManagementTools After installation, launch the AD CS configuration wizard: Role Services: Choose Certification Authority (and Web Enrollment if prompted). Setup Type: Select Enterprise CA (since this CA will integrate with AD DS). CA Type: Select Subordinate CA (this indicates it will get its cert from an existing root CA). Private Key: Choose “Create a new private key” (we’ll generate a new key pair for this CA). Cryptography: If using an HSM here as well, select the HSM’s CSP/KSP for the issuing CA’s key. Otherwise, choose a strong key length (2048+ bits, SHA256 or better for hash). CA Name: Provide a name (e.g., “Contoso Issuing CA”). This name will appear as the Issuer on certificates it issues. Certificate Request: The wizard will ask how you want to get the subordinate CA’s certificate. Choose “Save a certificate request to file”. Specify a path, e.g., C:\CertRequest\issuingCA.req. The wizard will generate a request file that we need to take to the Root CA for signing. (Since our Root CA is offline, this file transfer might be via secure USB or a network share when the root is temporarily online.) CA Database: Choose locations or accept defaults for the certificate DB and logs. Finish the configuration wizard, which will complete pending because the CA doesn’t have a certificate yet. The AD CS service on this server won’t start until we import the issued cert from the root. Step 3: Integrate HSM on Issuing CA (Optional) If available, repeat the HSM setup on the Issuing CA: install HSM drivers, initialize it, and generate/secure the key for the subordinate CA on the HSM. Ensure you chose the HSM provider during the above configuration so that the issuing CA’s private key is stored in the HSM. Even though this CA is online, an HSM still greatly enhances security by protecting the private key from extraction. The issuing CA’s HSM may not require multiple custodians to activate (as it needs to run continuously), but should still be physically secured. Step 4: Obtain the Issuing CA’s Certificate from the Root CA Now we have a pending request (issuingCA.req) for the subordinate CA. To get its certificate: Transport the request to the Root CA: Copy the request file to the offline Root CA (via secure means – e.g., formatted new USB stick). Start up the Root CA (in a secure, offline setting) and open the Certification Authority console. Submit the request on Root CA: Right-click the Root CA in the CA console -> All Tasks -> Submit new request, and select the .req file. The request will appear in the Pending Requests on the root. Issue the subordinate CA certificate: Find the pending request (it will list the Issuing CA’s name). Right-click and choose All Tasks > Issue. The subordinate CA’s certificate is now issued by the Root CA. Export the issued certificate: Still on the Root CA, go to Issued Certificates, find the newly issued subordinate CA cert (you can identify it by the Request ID or by the name). Right-click it and choose Open or All Tasks > Export to get the certificate in a file form. If using the console’s built-in “Export” it might only allow binary; alternatively use the certutil command: certutil -dup <RequestID> .\ContosoIssuingCA.cer or simply open and copy to file. Save the certificate as issuingCA.cer. Also make sure you have a copy of the Root CA’s certificate (if not already done). Publish Root CA cert and CRL as needed: Before leaving the Root CA, you may also want to ensure the Root’s own certificate and latest CRL are available to the issuing CA and clients. If not already done in Step 5 of root deployment, export the Root CA cert (DER format) and copy the CRL file. You might use certutil -crl again if some time has passed since initial CRL. Now take the issuingCA.cer file (and root cert/CRL files) and move them back to the Issuing CA server. Step 5: Install the Issuing CA’s Certificate and Complete Configuration On the Issuing CA server (which is still waiting for its CA cert): Install the subordinate CA certificate: In Server Manager or the Certification Authority console on the Issuing CA, there should be an option to “Install CA Certificate” (if the AD CS configuration wizard is still open, it will prompt for the file; or otherwise, in the CA console right-click the CA name > All Tasks > Install CA Certificate). Provide the issuingCA.cer file obtained from the root. This will install the CA’s own certificate and start the CA service. The Issuing CA is now operational as a subordinate CA. Alternatively, use PowerShell: certutil -installcert C:\CertRequest\issuingCA.cer This installs the cert and associates it with the pending key. Trust the Root CA certificate: Because the Issuing CA is domain-joined, when you install the subordinate cert, it might automatically place the Root CA’s certificate in the Trusted Root Certification Authorities store on that server (and possibly publish it to AD). If not, you should manually install the Root CA’s certificate into the Trusted Root CA store on the Issuing CA machine (using the Certificates MMC or certutil -addstore -f Root rootCA.cer). This step prevents any “chain not trusted” warnings on the Issuing CA and ensures it trusts its parent. In an enterprise environment, you would also distribute the root certificate to all client machines (e.g., via Group Policy) so that they trust the whole chain. Import Root CRL: Copy the Root CA’s CRL (*.crl file) to the Issuing CA’s CRL distribution point location (e.g., C:\Windows\System32\CertSrv\CertEnroll\ if that’s the directory served by the web server). This matches the HTTP URL we configured on the root. Place the CRL file there and ensure it is accessible (the Issuing CA’s IIS might need to serve static .crl files; often, if Web Enrollment is installed, the CertEnroll folder is under C:\Inetpub\wwwroot\CertEnroll). At this point, the subordinate CA and any client hitting the HTTP URL can retrieve the root’s CRL. The subordinate CA is now fully established. It holds a certificate issued by the Root CA (forming a complete chain of trust), and it’s ready to issue end-entity certificates. Step 6: Configure Issuing CA Settings and Start Services Start the Certificate Services: If the CA service (CertSvc) isn’t started automatically, start or restart it. On PowerShell: Restart-Service certsvc The CA should show as running in the CA console with the name “Contoso Issuing CA” (or your chosen name). Configure Certificate Templates: Because this is an Enterprise CA, it can utilize certificate templates stored in Active Directory to simplify issuing common cert types (user auth, computer auth, web server SSL, etc.). By default, some templates (e.g., User, Computer) are available but not issued. In the Certification Authority console under Certificate Templates, you can choose which templates to issue (e.g., right-click > New > Certificate Template to Issue, then select templates like “User” or “Computer”). This lab guide doesn’t require specific templates but know that only Enterprise CAs can use templates. Templates define the policies and settings (cryptography, enrollment permissions, etc.) for issued certificates. Ensure you enable only the templates needed and configure their permissions appropriately (e.g., allow the appropriate groups to enroll). Set CRL publishing schedule: The Issuing CA will automatically publish its own CRL (for certificates it issues) at intervals. You can adjust the CRL and Delta CRL publication interval in the CA’s Properties > CRL Period. A common practice is a small base CRL period (e.g., 1 week or 2 weeks) for issuing CAs, because they may revoke user certs more frequently; and enable Delta CRLs (published daily) for timely revocation information. Make sure the CDP/AIA for the Issuing CA itself are properly configured too (the wizard usually sets LDAP and HTTP locations, but verify in the Extensions tab). In a lab, the default settings are fine. Web Enrollment (if installed): You can verify the web enrollment by browsing to http://<IssuingCA>/certsrv. This web UI allows browser-based certificate requests. It’s a legacy interface mostly, but for testing it can be used if your clients aren’t domain-joined or if you want a manual request method. In modern use, the Certificate Enrollment Web Service/Policy roles or auto-enrollment via Group Policy are preferred for remote and automated enrollment. At this stage, your PKI is operational: the Issuing CA trusts the offline Root CA and can issue certificates. The Root CA can be kept offline with confidence that the subordinate will handle all regular work. Validation and Testing of the PKI It’s important to verify that the PKI is configured correctly: Check CA status: On the Issuing CA, open the Certification Authority console and ensure no errors. Verify that the Issuing CA’s certificate shows OK (no red X). On the Root CA (offline most of the time), you can use the Pkiview.msc snap-in (Microsoft PKI Health Tool) on a domain-connected machine to check the health of the PKI. This tool will show if the CDPs/AIA are reachable and if certificates are properly published. Trust chain on clients: On a domain-joined client PC, the Root CA certificate should be present in the Trusted Root Certification Authorities store (if the Issuing CA was installed as Enterprise CA, it likely published the root cert to AD automatically; you can also distribute it via Group Policy or manually). The Issuing CA’s certificate should appear in the Intermediate Certification Authorities store. This establishes the chain of trust. If not, import the root cert into the domain’s Group Policy for Trusted Roots. A quick test: on a client, run certutil -config "ISSUINGCA\\Contoso Issuing CA" -ping to see if it can contact the CA (or use the Certification Authority MMC targeting the issuing CA). Enroll a test certificate: Try to enroll for a certificate from the Issuing CA. For instance, from a domain-joined client, use the Certificates MMC (in Current User or Computer context) and initiate a certificate request for a User or Computer certificate (depending on templates issued). If auto-enrollment is configured via Group Policy for a template, you can simply log on a client and see if it automatically receives a certificate. Alternatively, use the web enrollment page or certreq command to submit a request. The request should be approved and a certificate issued by "Contoso Issuing CA". After enrollment, inspect the issued certificate: it should chain up to "Contoso Root CA" without errors. Ensure that the certificate’s CDP points to the URL we set (and try to browse that URL to see the CRL file), and that the AIA points to the root cert location. Revocation test (optional): To test CRL behavior, you could revoke a test certificate on the Issuing CA (using the CA console) and publish a new CRL. On the client, after updating the CRL, the revoked certificate should show as revoked. For the Root CA, since it shouldn’t issue end-entity certs, you wouldn’t normally revoke anything except potentially the subordinate CA’s certificate (which would be a drastic action in case of compromise). By issuing a test certificate and validating the chain and revocation, you confirm that your two-tier PKI lab is functioning correctly. Maintaining the PKI: CRLs, Key Ceremonies, and Security Procedures Deploying the PKI is only the beginning. Proper maintenance and operational procedures are crucial to ensure the PKI remains secure and reliable over time. Periodic CRL Updates for the Offline Root: The Root CA’s CRL has a defined validity period (set during configuration, often 6 or 12 months for offline roots). Before the CRL expires, the Root CA must be brought online (in a secure environment) to issue a new CRL. It’s recommended to schedule CRL updates periodically (e.g., semi-annually) to prevent the CRL from expiring. An expired CRL can cause certificate chain validation to fail, potentially disrupting services. Typically, organizations set the offline root CRL validity so that publishing 1-2 times a year is sufficient. When the time comes: Start the Root CA (ensuring the system clock is correct). Run certutil -crl to issue a fresh CRL. Distribute the new CRL: copy it to the HTTP CDP location (overwrite the old file) and, if applicable, use certutil -dspublish -f RootCA.crl to update it in Active Directory. Verify that the new CRL’s next update date is extended appropriately (e.g., another 6 months out). Clients and the Issuing CA will automatically pick up the new CRL when checking for revocation. (The Issuing CA, if configured, might cache the root CRL and need a restart or certutil -setreg ca\CRLFlags +CRLF_REVCHECK_IGNORE_OFFLINE tweak if the root CRL expires unexpectedly. Keeping the schedule prevents such issues.) Issuing CA CRL and OCSP: The Issuing CA’s CRLs are published automatically as it is online. Ensure the IIS or file share hosting the CRL is accessible. Optionally, consider setting up an Online Responder (OCSP) for real-time status checking, especially if CRLs are large or you need faster revocation information. OCSP is another AD CS role service that can be configured on the issuing CA or another server to answer certificate status queries. This might be beyond a simple lab, but it’s worth mentioning for completeness. Key Ceremonies and Documentation: For production environments (and good practice even in labs), formalize the process of handling CA keys in a Key Ceremony. A key ceremony is a carefully controlled process for activities like generating the Root CA’s key pair, installing the CA, and signing subordinate certificates. It often involves multiple people to ensure no single person has unilateral control (principle of dual control) and to witness the process. Best practices for a Root CA key ceremony include: Advance Planning: Create a step-by-step script of the ceremony tasks. Include who will do what, what materials are needed (HSMs, installation media, backup devices, etc.), and the order of operations. Multiple trusted individuals present: Roles might include a Ceremony Administrator (leads the process), a Security Officer (responsible for HSM or key material handling), an Auditor (to observe and record), etc. This prevents any one person from manipulating the process and increases trust. Secure environment: Conduct the ceremony in a secure location (e.g., a locked room) free of recording devices or unauthorized personnel. Ensure the Root CA machine is isolated (no network), and ideally that BIOS/USB access controls are in place to prevent any malware. Generate keys with proper controls: If using an HSM, initialize and generate the key with the required number of key custodians each providing part of the activation material (e.g., smartcards or passphrases). Immediately back up the HSM partition or key to secure media (requiring the same custodians to restore). Sign subordinate CA certificate: As part of the ceremony, once the root key is ready, sign the subordinate’s request. This might also be a witnessed step. Document every action: Write down each command run, each key generated, serial numbers of devices used, and have all participants sign an acknowledgment of the outcomes. Also record the fingerprints of the generated Root CA certificate and any subordinate certificate to ensure they are exactly as expected. Secure storage: After the ceremony, store the Root CA machine (if it’s a laptop or VM) and HSM tokens in a tamper-evident bag or safe. The idea is to make it evident if someone tries to access the root outside of an authorized ceremony. While a full key ceremony might be overkill for a small lab, understanding these practices is important. Even in a lab, you can simulate some aspects (for learning), like documenting the procedure of taking the root online to sign the request and then locking it away. These practices greatly increase the trust in a production PKI by ensuring transparency and accountability for critical operations. Backup and Recovery Plans: Both CAs’ data should be regularly backed up: For the Root CA: since it’s rarely online, backup after any change. Typically, you’d back up the CA’s private key and certificate once (right after setup or any renewal). Store this securely offline (separate from the server itself). Also back up the CA database if it ever issues more than one cert (for root it might not issue many). For the Issuing CA: schedule automated backups of the CA database and private key. You can use the built-in certutil -backup or Windows Server Backup (which is aware of the AD CS database). Keep backups secure and test restoration procedures. Having a documented recovery procedure for the CA is crucial for continuity. Also consider backup of templates and any scripts. Maintain spare hardware or VMs in case you need to restore the CA on new hardware (especially for the root, having a procedure to restore on a new machine if the original is destroyed). Security maintenance: Apply OS updates to the CAs carefully. For the offline root, patch it offline if possible (offline servicing or connecting it briefly to a management network). For the issuing CA, treat it as a critical infrastructure server: limit its exposure (firewall it so only required services are reachable), monitor its event logs (enable auditing for Certificate Services events, which can log each issuance and revocation), and employ anti-malware tools with caution (whitelisting the CA processes to avoid interference). Also, periodically review the CA’s configuration and certificate templates to ensure they meet current security standards (for example, deprecate any weak cryptography or adjust validity periods if needed). By following these maintenance steps and best practices, your two-tier PKI will remain secure and trustworthy over time. Remember that PKI is not “set and forget” – it requires operational diligence, but the payoff is a robust trust infrastructure for your organization’s security. Additional AD CS Features and References Active Directory Certificate Services provides more capabilities than covered in this basic lab. Depending on your needs, you might explore: Certificate Templates: We touched on templates; they are a powerful feature on Enterprise CAs to enforce standardized certificate settings. Administrators can create custom templates for various use cases (SSL, S/MIME email, code signing) and control enrollment permissions. Understanding template versions and permissions is key for enterprise deployments. (Refer to Microsoft’s documentation on Certificate template concepts in Windows Server for details on how templates work and can be customized.) Web Services for Enrollment: In scenarios with remote or non-domain clients, AD CS offers the Certificate Enrollment Web Service (CES) and Certificate Enrollment Policy Web Service (CEP) role services. These allow clients to fetch enrollment policy information and request certificates over HTTP or HTTPS, even when not connected directly to the domain. They work with the certificate templates to enable similar auto-enrollment experiences over the web. See Microsoft’s guides on the Certificate Enrollment Web Service overview and Certificate Enrollment Policy Web Service overview for when to use these. Network Device Enrollment Service (NDES): This AD CS role service implements the Simple Certificate Enrollment Protocol (SCEP) to allow devices like routers, switches, and mobile devices to obtain certificates from the CA without domain credentials. NDES acts as a proxy (Registration Authority) between devices and the CA, using one-time passwords for authentication. If you need to issue certificates to network equipment or MDM-managed mobile devices, NDES is the solution. Microsoft Docs provide a Network Device Enrollment Service(NDES) overview and even details on using a policy module with NDES for advanced scenarios (like customizing how requests are processed or integrating with custom policies). Online Responders (OCSP): As mentioned, an Online Responder can be configured to answer revocation status queries more efficiently than CRLs, especially useful if your CRLs grow large or you have high-volume certificate validation (VPNs, etc.). AD CS’s Online Responder role service can be installed on a member server and configured with the OCSP Response Signing certificate from your Issuing CA. Monitoring and Auditing: Windows Servers have options to audit CA events. Enabling auditing can log events such as certificate issuance, revocation, or changes to the CA configuration. These logs are important in enterprise PKI to track who did what (for compliance and security forensics). Also, tools like the PKI Health Tool (pkiview.msc) and PowerShell cmdlets (like Get-CertificationAuthority, Get-CertificationAuthorityCertificate) can help monitor the health and configuration of your CAs. Conclusion By following this guide, you have set up a secure two-tier PKI environment consisting of an offline Root CA and an online Issuing CA. This design, which uses an offline root, is considered a security best practice for enterprise PKI deployments because it reduces the risk of your root key being compromised. With the offline Root CA acting as a hardened trust anchor and the enterprise Issuing CA handling day-to-day certificate issuance, your lab PKI can issue certificates for various purposes (HTTPS, code signing, user authentication, etc.) in a way that models real-world deployments. As you expand this lab or move to production, always remember that PKI security is as much about process as technology. Applying strict controls to protect CA keys, keeping software up to date, and monitoring your PKI’s health are all part of the journey. For further reading and official guidance, refer to these Microsoft documentation resources: 📖 AD CS PKI Design Considerations: PKI design considerations using Active Directory Certificate Services in Windows Server helps in planning a PKI deployment (number of CAs, hierarchy depth, naming, key lengths, validity periods, etc.). This is useful to read when adapting this lab design to a production environment. It also covers configuring CDP/AIA and why offline roots usually don’t need delta CRLs. 📖 AD CS Step-by-Step Guides: Microsoft’s Test Lab Guide Test Lab Guide: Deploying an AD CS Two-Tier PKI Hierarchy walk through a similar scenario.Evolving the Windows User Model – Introducing Administrator Protection
Previously, in part one, we outlined the history of the multi-user model in Windows, how Microsoft introduced features to secure it, and in what ways we got it right (and wrong). In the final part of this series, we will describe how Microsoft intends to raise the security bar via its new Administrator protection (AP) feature. Core Principles for Administrator Protection As the main priority, Administrator protection aims to provide a strong security boundary between elevated and non-elevated user contexts. There are several additional usability goals that we will cover later, but for security, Administrator protection can be summarized by the following five principles: Users operate within the Principle of Least Privilege Administrator privileges only persist for the duration of the task for which they were invoked Strong separation between elevated and non-elevated user accounts, except for paths of intentional access Elevation actions must be explicit (e.g. no silent elevations) Allowing a more granular use of elevated privileges by applications, rather than the “up-front” elevation practice common in User Account Control (UAC) Specifically, principles two and three represent major changes to the existing design of the Windows user model, while principles one and four are intent on fulfilling promises of previous features (standard user and, to a lesser extent, UAC) and rolling back changes which degraded security (auto-elevation), respectively. What Does Administrator Protection Fix and How? Administrator protection is nearly as much about what it removes as to what it adds. Recall, beginning with Windows Vista, the split-token administrator user type was added to allow a user to run as both standard user and administrator depending on the level of privilege required for a specific task. It was originally seen to make standard user more viable for wide-spread adoption and to enforce the Principle of Least Privilege. However, the features did not fully live up to expectations as UAC bypasses were numerous following the release of Windows 7. As a refresher, when a user was configured as a split-token admin, they would receive two access tokens upon logon – a full privilege, “elevated” administrator token with admin group policy set to “Enabled” and a restricted, “unelevated” access token with admin group policy set to “DenyOnly”. Depending on the required run level of an application, one token or the other would be used to create the process. Administrator protection changes the paradigm via System Managed Administrator Accounts (SMAA) – a local administrator account which is linked to a specific standard user account. Upon elevation, if a SMAA does not exist already it is created. Each SMAA is a separate user profile and member of the Administrators group. It is a local account named via the following scheme utilizing extra digits in the unlikely event of a collision: Local Account: WIN-ABC123\BobFoo SMAA: WIN-ABC123\admin_BobFoo Or on collision: Local Account: WIN-ABC123\BobFoo (the account to be SMAA-linked) Local Account: WIN-ABC123\admin_BobFoo (another standard user account, oddly named) SMAA: WIN-ABC123\admin1_BobFoo Similarly, for domain accounts, the scheme remains the same, except the SMAA will still be a local account: Domain Account: Redmond\BobFoo SMAA: WIN-ABC123\admin_BobFoo To ensure these accounts can’t be abused, they are created as password-less accounts with additional logon restrictions to ensure only specific, SYSTEM processes are permitted to logon as the SMAA. Specifically, following an elevation request, a logon request is made via the Local Security Authority (LSA), and the following conditions are checked: Access Check. Call NtAccessCheck, including both an ACE for the SYSTEM account and a SYSTEM IL mandatory ACE with no read up, no write up, and no execute up. The access check must pass. Process Path. Call NtOpenProcess with the caller’s PID to obtain a process handle, then check the process image path via QueryFullProcessImageName. Compare the path to the hardcoded allow-list of binaries that are allowed to logon SMAA accounts. The astute reader may notice that process path checks are not enforceable security boundaries in Windows; rather, the check is a defense-in-depth measure to prevent SYSTEM processes such as WinLogon or RDP from exposing SMAA logon surface to the user. In fact, Process Execution Block (PEB) spoofing was a class of UAC bypass in which a trusted image path was faked by a malicious process. However, in this case the PEB is not queried, but instead the kernel EPROCESS object is used to query the image path. As such, the process path check will be used alongside an allowlist to prevent current and future system components from misusing SMAA. Splitting the Hive A major design compromise made with the split-token administrator model was that both “halves” of the user shared a common profile. Despite each token being appropriately restricted in its use, both restricted and admin-level processes could access shared resources such as the user file system and the registry. As such, improper access restrictions on a given file or registry key would allow a restricted user the ability to influence a privileged process. In fact, improper access controls on shared resources were the source of many classic UAC bypasses. As an example, when the Event Viewer application, “eventvwr.exe”, attempts to launch “mmc.exe” as a High Integrity Level (IL) process, it searches two registry locations to find the executable path (1): HKCU\Software\Classes\mscfile\shell\open\command HKCR\mscfile\shell\open\command In most circumstances, the first registry location does not exist, so the second is used to launch the process. However, an unprivileged process running within the restricted user context can create the missing key; this would then allow the attack to run any executable it wished at High IL. As a bonus for the attacker, this attack was silent as Event Viewer is a trusted Windows application and allows for “auto-elevation” meaning no UAC prompt would be displayed. $registryPath = "HKCU:\Software\Classes\mscfile\shell\open\command" $newValue = "C:\Windows\System32\cmd.exe" # Check if the registry key exists if (-not (Test-Path $registryPath)) { # Create the registry key if it doesn't exist New-Item -Path "HKCU:\Software\Classes\mscfile\shell\open" -Name "command" -Force | Out-Null `}` # Set the registry value Set-ItemProperty -Path $registryPath -Name "(default)" -Value $newValue # Run mmc.exe to auto-elevate cmd.exe Start-Process “mmc.exe” Similarly, the Windows Task Scheduler – which configures processes to run periodically – could be exploited to run arbitrary commands or executables in an elevated context. These attacks worked similarly in that they used writable local environment variables to overload system variables such as %WINDIR% to allow an attack to execute arbitrary applications with elevated privileges – with SilentCleanup being a particular favorite (2). Such attacks were attractive as an unprivileged process could also trigger the scheduled task to run at any time. New-ItemProperty -Path "HKCU:\Environment" -Name "windir" -Value "cmd.exe /k whoami & " -PropertyType ExpandString; schtasks.exe /Run /TN \Microsoft\Windows\DiskCleanup\SilentCleanup /I As separate-but-linked accounts, each with its own profile, registry hives are no longer shared. Thus, classic UAC bypasses, such as the registry key manipulation and environment variable (like many things in Windows, environment variables are backed in the registry) overloading attacks are mitigated. As an added benefit administrator tokens can now be created on-demand and discarded just as quickly, thus limiting exposure of the privileged token to the lifetime of the requesting process. Rolling Back Auto-Elevations When auto-elevation was added in Windows 7, it was primarily done so to improve the user experience and allow simpler administration of a Windows machine. Unfortunately, despite several restrictions placed on applications allowed to auto-elevate, the feature introduced a huge hole in the Windows security model and opened a number of new avenues for UAC bypass. Most prevalent of these bypasses were those which exploited the auto-elevating COM interface IFileOperation. Attackers would leverage this interface to write malicious DLLs to secure locations – a so-called “DLL Hijacking” attack. The attack would work whenever a process met all of the conditions for auto-elevation but ran at the Medium Integrity Level (IL). The malicious process would inject code into the target process and request the DLL payload be written to a secure path via IFileOperation. Whenever the DLL was loaded by an elevated process, the malicious code would be run, giving the attacker full privileges on the system. With Administrator protection, auto-elevation is removed. Users will notice an increase in consent prompts, though many fewer than the Vista days as much work has been done to clean up elevation points in most workflows. Additionally, users and administrators will have the option to configure elevation prompts as “credentialed” (biometric/password/PIN) via Windows Hello or simply confirmation prompts. This simple change trades some user convenience for a reduction in attack surface of roughly 92 auto-elevating COM interfaces, 11 DLL Hijacks, and 23 auto-elevating apps. Of the 79 known UAC bypasses tested, all but one are now fully or partially mitigated. The remaining open issue around token manipulation attacks has been assigned MSRC cases and will be addressed. It should be noted that not all auto-elevations have been removed. Namely, the Run and RunOnce registry keys found in the HKEY_LOCAL_MACHINE hive will still auto-elevate as needed. Appropriately, these keys are ACL’d such that only an administrator can modify them. Improving Useability Administrator protection is not limited to security-focused changes only – improved useability is also a major focal point of the feature. Chief amongst the areas targeted for improvement is the removal of unnecessary elevations and “dead-ends”. Specifically, dead-ends occur when a functional pathway which requires administrator privileges does not account for a user operating as a standard user and thus presents no elevation path at all, resulting in the user interface either displaying the setting as disabled or not at all. In such cases, a so-called “over-the-shoulder” elevation is required – the same underlying mechanism used when elevating to the SMAA user in AP. Such scenarios represent huge inconvenience for non-Administrator accounts in both AP and non-AP enabled configurations. One example of this scenario was the group policy editor (gpedit.exe). When launching as a standard user, an error prompt would be displayed, and the app would be launched in an unusable state. More Work To Be Done Administrator protection represents a huge jump in the security of the Windows OS. However, as always, there is more work to be done. While AP has mitigated large classes of vulnerabilities, some remain, albeit in a diminished state. DLL hijacking attacks prior to AP primarily relied on abusing the auto-elevating IFileOperation COM interface to write a malicious DLL to a secure path. As auto-elevation has been removed, this path no longer exists. However, situations where an unsigned DLL is loaded from an insecure path still represent a potential AP bypass. Note that the user will still be prompted for elevation in such a scenario but may not be aware that a malicious DLL is being included in the process. Token manipulation bypasses such as those shown by James Forshaw and splinter_code, remain a class of potential exploitation. Elevation prompts are shown only before creation of an elevated token, not use. Therefore, should additional pathways be discovered where an elevated token can be obtained by a malicious process, AP would not be positioned to stop it from silently elevating. However, MSRC cases for known variants of token manipulation/reuse attack have been filed and fixes are currently in-development. Lastly, attacks which rely on obtaining a UIAccess capability from another running process are partially mitigated by AP. Previously, UAC bypass attacks would launch an auto-elevating app, such as mmc.exe, and then obtain a UIAccess-enabled token — a token which gives a lower-privileged process the ability to manipulate the UI of a higher-privileged process, typically used for accessibility features. With AP enabled, all attempts to launch an elevated process would be met with a consent prompt which an attacker would be unable manipulate with a UIAccess token alone. However, in situations where a user has previously elevated a running process, an attack would be able to obtain a UIAccess token and manipulate the UI with no additional consent prompts. This list is not exhaustive, it is likely edge cases will pop up which will require attention. Fortunately Administrator protection is covered by the Windows Insider Bug Bounty Program and internal efforts by MORSE and others will continue to identify remaining issues. A Welcome Security Boundary We In MORSE review quite a few features in Windows and are big fans of Administrator protection. It addresses many gaps left by UAC today and adds protections which for all intents and purposes simply did not exist before. The feature is far from complete, usability improvements are needed, and there are some remaining bugs which will take time to resolve. However, the short-term inconvenience, is worth long term security benefit to users. While Administrator protection will certainly experience some growing pains, even in its current state, it’s a leap forward for user security. Going forward, we encourage those users who prioritize strong security to give Administrator protection a try. If you encounter an issue, send us feedback using the feedback tool. Lastly, for app developers, we ask they update their applications to support Administrator protection, as it will eventually become the default option in Windows. References UAC Bypass – Event Viewer – Penetration Testing Lab Tyranid's Lair: Exploiting Environment Variables in Scheduled Tasks for UAC Bypass Tyranid's Lair: Bypassing UAC in the most Complex Way Possible! Bypassing UAC with SSPI Datagram Contexts Administrator protection on Windows 11 | Microsoft Community HubStrengthen your data security posture in the era of AI with Microsoft Purview
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