ANNOUNCE: Security Implications of Windows Access Tokens Whitepaper

[luke.jennings () mwrinfosecurity com]

Hey guys,

I recently got round to writing the whitepaper version of my Defcon 15 and CCC talk. For those who are interested, 
please find the abstract, PDF link and sourceforge link to the accompanying tool below: -

http://www.mwrinfosecurity.com/publications/mwri_security-implications-of-windows-access-tokens_2008-04-14.pdf
http://sourceforge.net/projects/incognito

ABSTRACT

This whitepaper discusses the security exposures that can occur due to the manner in which access tokens are 
implemented in the Microsoft® Windows Operating System. A brief overview of the intended function, design and 
implementation of Windows access tokens is given, followed by a discussion of the relevant security consequences of 
their design. More specific technical details are then given on how the features of Windows access tokens can be used 
to perform powerful post-exploitation functions during penetration testing, along with a basic methodology for 
including an assessment of the vulnerabilities exposed through tokens in a standard penetration test. Discussion is 
also included about why many corporate environments (assessed during penetration tests conducted by MWR InfoSecurity) 
have been found to not be operating in a manner which limits the risk of such issues. Finally, best practice advice is 
given on how to defend against these attacks.

It must be noted that the security issues discussed in this white paper do not represent a flaw in the Microsoft® 
Windows Operating System but are an expected consequence based on the design and implementation of Windows access 
tokens. The important point is that many corporate environments do not account for these issues within their security 
strategy and, consequently, the controls in many of these environments are not sufficient to withstand the techniques 
discussed here.

Additionally, it is acknowledged that the security implications of Windows access tokens have been discussed before 
both in general terms and to different degrees of technical detail. This document is not intended to present such 
discussions as being fundamentally new; instead it is intended to collate some of the existing knowledge, introduce 
some new findings and to demonstrate why many years after the general principles discussed were highlighted, many 
corporate environments are still vulnerable to these issues.

This paper is based upon research originally presented by the author at Defcon 15 [1] and Chaos Computer Congress (CCC) 
2007 [2].

Cheers,

Luke