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Security Science

Mitigating Software Vulnerabilities

Tuesday, July 12, 2011

How can you protect yourself, your business, and your customers when faced with an unknown or unpatched software vulnerability? This question can be difficult to answer but it is nevertheless worthy of thoughtful consideration. One particularly noteworthy answer to this question is provided in the form of exploit mitigation technologies such as DEP and ASLR, which are designed to make it difficult and costly for an attacker to exploit a software vulnerability.

New Internet Explorer vulnerability affecting all versions of IE

Wednesday, December 22, 2010

Today we released Security Advisory 2488013 to notify customers of a new publicly-disclosed vulnerability in Internet Explorer (IE). This vulnerability affects all versions of IE. Exploiting this vulnerability could lead to unauthorized remote code execution inside the iexplore.exe process. Proof-of-concept exploit bypasses ASLR and DEP The Metasploit project recently published an exploit for this vulnerability using a known technique to evade ASLR (Address Space Layout Randomization) and bypass DEP (Data Execution Prevention).

On the effectiveness of DEP and ASLR

Wednesday, December 08, 2010

DEP (Data Execution Prevention) and ASLR (Address Space Layout Randomization) have proven themselves to be important and effective countermeasures against the types of exploits that we see in the wild today. Of course, any useful mitigation technology will attract scrutiny, and over the past year there has been an increasing amount of research and discussion on the subject of bypassing DEP and ASLR [1,2].

The Enhanced Mitigation Experience Toolkit 2.0 is Now Available

Thursday, September 02, 2010

Today we are pleased to announce the availability of the Enhanced Mitigation Experience Toolkit (EMET) version 2.0. Users can click here to download the tool free of charge. For those who may be unfamiliar with the tool, EMET provides users with the ability to deploy security mitigation technologies to arbitrary applications.

Using code coverage to improve fuzzing results

Wednesday, February 24, 2010

Hi all, I’m Lars Opstad, an engineering manager in the MSEC Science group supporting the SDL within Microsoft. I wanted to share with you some of the ways that we are improving our internal security practices, specifically in the area of file fuzzing. Many fuzzers take a good file (template) as a starting point for creating malformed content.

SEHOP per-process opt-in support in Windows 7

Friday, November 20, 2009

In a previous blog post we discussed the technical details of Structured Exception Handler Overwrite Protection (SEHOP) which is an exploit mitigation feature that was first introduced in Windows Vista SP1 and Windows Server 2008 RTM. SEHOP prevents attackers from being able to use the Structured Exception Handler (SEH) overwrite exploitation technique when attempting to exploit certain types of software vulnerabilities.

Preventing the exploitation of user mode heap corruption vulnerabilities

Tuesday, August 04, 2009

Over the past few months we have discussed a few different defense in depth mitigations (like GS [pt 1, pt2], SEHOP, and DEP [pt 1, pt 2]) which are designed to make it harder for attackers to successfully exploit memory safety vulnerabilities in software. In addition to the mitigations that we’ve discussed so far, a significant amount of effort has gone into hardening the Windows heap manager in order to complicate the exploitation of heap-based memory corruption vulnerabilities.