Feb 23 2023 07:54 AM
Written by Shawn Hernan, Partner Group Engineering Manager, Azure Security
In the first blog in this series, we discussed our extensive investments in securing Microsoft Azure, including more than 8500 security experts focused on securing our products and services, our industry-leading bug bounty program, our 20-year commitment to the Security Development Lifecycle (SDL), and our sponsorship of key Open-Source Software security initiatives. We also introduced some of the updates we are making in response to the changing threat landscape including improvements to our response processes, investments in Secure Multitenancy, and the expansion of our variant hunting efforts to include a global, dedicated team focused on Azure. In this blog, we’ll focus on variant hunting as part of our larger overall security program.
Variant hunting is an inductive learning technique, going from the specific to the general. Using newly discovered vulnerabilities as a jumping-off point, skilled security researchers look for additional and similar vulnerabilities, generalize the learnings into patterns, and then partner with engineering, governance, and policy teams to develop holistic and sustainable defenses. Variant hunting also looks at positive patterns, trying to learn from success as well as failure, but through the lens of real vulnerabilities and attacks, asking the question, “why did this attack fail here, when it succeeded there?”
In addition to detailed technical lessons, variant hunting also seeks to understand the frequency at which certain bugs occur, the contributing causes that permitted them to escape SDL controls, the architectural and design paradigms that mitigate or exacerbate them, and even the organizational dynamics and incentives that promote or inhibit them. It is popular to do root cause analysis, looking for the single thing that led to the vulnerability, but variant hunting seeks to find all of the contributing causes.
While rigorous compliance programs like the Microsoft SDL define an overarching scope and repeatable processes, variant hunting provides the agility to respond to changes in the environment more quickly. In the short term, variant hunting augments the SDL program by delivering proactive and reactive changes faster for cloud services, while in the long term, it provides a critical feedback loop necessary for continuous improvement.