Code Signing and UAC in Windows Vista havea relationship that should not be underestimated. Code Signing allowsUAC to provide a user with the details of an application's publisherand, thus, permits the user to ensure it is trusted before allowing itto elevate to full administrative privileges. Therefore, my recentobservation has left me dumbfounded.
The observation was this: if a signed binary is modified on diskand, thus, the code signing signature invalidated, you don’t get a bigklaxon going off with the computer screaming, “Danger Will Robinson!Danger!” Instead, the binary is simply treated as if it isn’t signed.Why is this an issue? The simple reason is that if, for example, youhave a world of poor file permissions (looking squarely at third-partysoftware here) and the user running as a restricted administrator canmodify a binary that is allowed to elevate, you could end up in asticky situation. That is, if a user is familiar with the fact that...
Greetings. For the last four months we have been busy taking a lookat the release (RTM) version of Windows Vista in an effort to updateour Windows Vista Network Attack Surface Analysis report fromlast July, which covered beta builds of Vista. To broaden and deepenour research, we have retested the results in the first report andexpanded our investigation of certain topics.
As of today, the new reportis available to you. The paper is 118 pages long, but don't worry, youdon't have to read it all! You can skip to the parts you are mostinterested in, or take a look at the 13 pages that summarize theresults in the paper. In addition, the appendices provide details ofour methodology and results. We hope you find this report useful as aWindows Vista network reference, and we hope you find value in both thedetailed security analysis and in the broad overview.
The media surrounding the effectiveness of Windows Vista's newsecurity features has (in my opinion) just begun. Microsoft's reach iswell beyond that of any other software vendor in the world, and withthis achievement comes fame, power, and a corporate life under amicroscope. To honor this tradition, I previously posted an entryabout the effects of malicious code executed under a default Vistaenvironment; if you haven't read it, you are certainly encouraged to.This research has now been completed and this new entry should serve asa compliment to my previous post. A paper detailing the full researchhas been made available here.
The outcome of the research:
In my previous blog, I mentioned that about seventy...
When I started this project, I had one goal in mind – to understandwhich binaries in Windows Vista were not /GS compiled. While this mayseem rather simple on the surface, as I started to dig, it became alittle more complex. That said, my goal was achievable and today I’mhappy to present my findings.
The purpose of my paper "Analysis of GS Protection in Windows Vista"was to show which binaries under a default installation of WindowsVista 32bit RTM were not protected by the Visual Studio 2005 /GScompiler flag. This, in turn, was designed to help Symantec and ourclients understand any exposure, either direct or indirect, which mayresult from this lack of protection.
The abstract for my paper is as follows:
Visual Studio 2002 introduced the Buffer Security Check(GS) option to protect stack variables from overflows that resulted inarbitrary code...
ASLR (Address Space Layout Randomization) is one of the cornerstones of Windows Vista and its enhanced security posture. ASLR workson the basis that it will move an application and its associated memoryaround, either each time it’s executed or when the host is rebooted,depending on the element concerned. The purpose of this is to hinder aclass of vulnerabilities commonly referred to as memory manipulation vulnerabilitiesby making it difficult for an attacker to know where an application isin memory. This would impede successful exploitation, which relies onfixed memory addresses.
Back in December, I decided to take a brief look at theimplementation of ASLR on Vista. I had seen some findings emerge duringits development, but these really didn’t show if the implementation wasgood, bad, or indifferent. Since my work load was winding down, as Ihad December off, and a tool I had written indicated there might besome problems, I decided to look at this in more detail. My...
