Vulnerability hunting with Semmle QL, part 2

The first part of this series introduced Semmle QL, and how the Microsoft Security Response Center (MSRC) are using it to investigate variants of vulnerabilities reported to us. This post discusses an example of how we’ve been using it proactively, covering a security audit of an Azure firmware component. This was part of a wider defense in depth security review of Azure services, exploring attack vectors from the point of view of a hypothetical adversary who has already penetrated at least one security boundary, and now sits in the operating environment of a service backend (marked with * on the diagram below).