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….


Eternal Synergy Exploit Analysis

Introduction Recently we announced a series of blog posts dissecting the exploits released by the ShadowBrokers in April 2017; specifically some of the less explored exploits. This week we are going to take a look at Eternal Synergy, an SMBv1 authenticated exploit. This one is particularly interesting because many of the exploitation steps are purely packet-based,…


Eternal Champion Exploit Analysis

Recently, a group named the ShadowBrokers published several remote server exploits targeting various protocols on older versions of Windows. In this post we are going to look at the EternalChampion exploit in detail to see what vulnerabilities it exploited, how it exploited them, and how the latest mitigations in Windows 10 break the exploit as-written….


Tales from the MSRC: from pixels to POC

Is this thing still on? It’s been a while since we’ve posted to this blog and we think it’s time to start posting deep technical content about Security Research & Defense (SRD) again. For readers who are new or may have forgotten, this blog is the home of the MSRC Vulnerabilities & Mitigations engineering team….