Security Research & Defense

Rusty construction shovel

We need a safer systems programming language

In our first post in this series, we discussed the need for proactively addressing memory safety issues. Tools and guidance are demonstrably not preventing this class of vulnerabilities; memory safety issues have represented almost the same proportion of vulnerabilities assigned a CVE for over a decade. We feel that using memory-safe languages will mitigate this …

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Rusty construction shovel

A proactive approach to more secure code

What if we could eliminate an entire class of vulnerabilities before they ever happened? Since 2004, the Microsoft Security Response Centre (MSRC) has triaged every reported Microsoft security vulnerability. From all that triage one astonishing fact sticks out: as Matt Miller discussed in his 2019 presentation at BlueHat IL, the majority of vulnerabilities fixed and …

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Time travel debugging: It’s a blast! (from the past)

The Microsoft Security Response Center (MSRC) works to assess vulnerabilities that are externally reported to us as quickly as possible, but time can be lost if we have to confirm details of the repro steps or environment with the researcher to reproduce the vulnerability. Microsoft has made our “Time Travel Debugging” (TTD) tool publicly available …

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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 …

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Local privilege escalation via the Windows I/O Manager: a variant finding collaboration

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services to help make our customers and the global online community more secure. We appreciate the excellent vulnerability research reported to us regularly from the security community, and we consider it a privilege to work with these researchers. One …

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Fuzzing para-virtualized devices in Hyper-V

Introduction Hyper-V is the backbone of Azure, running on its Hosts to provide efficient and fair sharing of resources, but also isolation. That’s why we, in the vulnerability research team for Windows, have been working in the background for years now helping secure Hyper-V. And why Microsoft invites security researchers across the globe to submit …

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Microsoft Security Servicing Criteria for Windows

One of our goals in the Microsoft Security Response Center (MSRC) is to be more transparent with security researchers and our customers on the criteria we use for determining when we intend to address a reported vulnerability through a security update. Our belief is that improving transparency on this topic helps provide clarity on how …

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Vulnerability hunting with Semmle QL, part 1

Previously on this blog, we’ve talked about how MSRC automates the root cause analysis of vulnerabilities reported and found. After doing this, our next step is variant analysis: finding and investigating any variants of the vulnerability. It’s important that we find all such variants and patch them simultaneously, otherwise we bear the risk of these …

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Analysis and mitigation of L1 Terminal Fault (L1TF)

In January 2018, Microsoft released an advisory and security updates for a new class of hardware vulnerabilities involving speculative execution side channels (known as Spectre and Meltdown). In this blog post, we will provide a technical analysis of a new speculative execution side channel vulnerability known as L1 Terminal Fault (L1TF) which has been assigned …

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