When Security Tools Go Bad

Noticed on milworm today PoC buffer overflows for both OllyDBG and ImpREC. This reminded me of a post I wrote last year about some vulnerabilities that were discovered in EnCase and the Sleuth Kit. These sorts of issues do get me thinking about how much, and how effectively, we verify the validity of the security tools we use.

At a forensic acquisition training course I attended recently, one of the items discussed was assuring and validating that the tools you use do not compromise the information you are acquiring. This is particularly important for chain of custody and tamper-proofing. You don’t want to use a particular piece of software, which claims to access a storage media without making any changes to it, only to discover that it has made minute changes. Or that a hardware device designed to prevent data being written to a hard-drive actually makes small changes to the drive itself.

This same principle applies to tools used for malware reverse engineering or software validation. You don’t want to find that the tools you’re using to try and determine if software is malicious, are exploitable by DLLs able to run foreign executables. If you aren’t careful with your testing environments, you may un-expectantly expose it to malware (in the bad way, not in the way that is controlled). This isn’t much of a problem if you run your reverse engineering tools in a virtualised environment, but if you don’t then you might find that you’ll have to spend some time rolling back or re-installing everything.

Being pragmatic of course, I don’t think anyone would expect you to be able to find the sorts of vulnerabilities as was found in this PoC. But sure, you’ll have to show some degree of rigour in validating your tools. Most of the time it will be sufficient to check for any current or previous vulnerabilities on security sites such as securityfocus, sans, securitytracker or milworm. Perhaps rigour around also means that you maintain an up-to-date tools list, including your licensing and version information. Perhaps you utilise Secunia’s software to ensure that all software is current.

I’m unsure how other people perform this process, or even if it’s necessary. Perhaps it’s only necessary in the forensic space. I’m not entirely sure. I’ve posted the question on the Security Catalyst Community so hopefully I’ll find out what other people think.

Posted by Christian 9 July 2008

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