Draft of Microsoft Security Servicing Commitments for Windows

Microsoft’s commitment to protecting customers from vulnerabilities in our products, services, and devices includes providing security updates that address these vulnerabilities when they are discovered. We understand that researchers have wanted better clarity around the security features, boundaries and mitigations which exist in Windows and the servicing commitments which come with them. We have drafted…


Analysis and mitigation of speculative store bypass (CVE-2018-3639)

In January, 2018, Microsoft published 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 an additional subclass of speculative execution side channel vulnerability known as Speculative Store Bypass (SSB) which has…


Hyper-V Debugging Symbols Are Publicly Available

The security of Microsoft’s cloud services is a top priority for us. One of the technologies that is central to cloud security is Microsoft Hyper-V which we use to isolate tenants from one another in the cloud. Given the importance of this technology, Microsoft has made and continues to make significant investment in the security of…


Triaging a DLL planting vulnerability

DLL planting (aka binary planting/hijacking/preloading) resurface every now and then, it is not always clear on how Microsoft will respond to the report. This blog post will try to clarify the parameters considered while triaging DLL planting issues.  It is well known that when an application loads a DLL without specifying a fully qualified path,…


KVA Shadow: Mitigating Meltdown on Windows

On January 3rd, 2018, Microsoft released an advisory and security updates that relate to a new class of discovered hardware vulnerabilities, termed speculative execution side channels, that affect the design methodology and implementation decisions behind many modern microprocessors. This post dives into the technical details of Kernel Virtual Address (KVA) Shadow which is the Windows…


Mitigating speculative execution side channel hardware vulnerabilities

On January 3rd, 2018, Microsoft released an advisory and security updates related to a newly discovered class of hardware vulnerabilities involving speculative execution side channels (known as Spectre and Meltdown) that affect AMD, ARM, and Intel CPUs to varying degrees. If you haven’t had a chance to learn about these issues, we recommend watching The…


Clarifying the behavior of mandatory ASLR 

Last week, the CERT/CC published an advisory describing some unexpected behavior they observed when enabling system-wide mandatory Address Space Layout Randomization (ASLR) using Windows Defender Exploit Guard (WDEG) and EMET on Windows 8 and above. In this blog post, we will explain the configuration issue that CERT/CC encountered and describe work arounds to enable the desired behavior. In…


VulnScan – Automated Triage and Root Cause Analysis of Memory Corruption Issues 

The Microsoft Security Response Center (MSRC) receives reports about potential vulnerabilities in our products and it’s the job of our engineering team to assess the severity, impact, and root cause of these issues. In practice, a significant proportion of these reports turn out to be memory corruption issues.  In order to root cause these issues,…


Moving Beyond EMET II – Windows Defender Exploit Guard

Since we last wrote about the future of EMET and how it relates to Windows 10 back in November 2016 (see Moving Beyond EMET), we have received lots of invaluable feedback from EMET customers and enthusiasts regarding the upcoming EMET end of life. Based on that feedback, we are excited to share significant new exploit…


EnglishmansDentist Exploit Analysis

Introduction We are continuing our series of blog posts dissecting the exploits released by ShadowBrokers in April 2017. After the first two posts about the SMB exploits known as EternalChampion and EternalSynergy, we’ll move this time to analyze a different tool and we’ll focus on the exploit named EnglishmansDentist designed to target Exchange Server 2003….