OpenBSD Journal

Executable Checksumming in OpenBSD 3.0

Contributed by Dengue on from the cool dept.

Adam VanderHook writes :
"The folks over at have released a paper (pdf) and source code (currently i386 only) about in-kernel MD5Sum comparisons at run time. The purpose? To help you detect binaries that have possibly been tampered with by an intruder."

(Comments are closed)

  1. By Anonymous () on

    I'm sorry, but if someone hacks your machine and you have loadable kernel modules enabled, you're screwed. MD5 checksumming in the kernel isn't helpful as, a kernel module can just tell that piece of code "These aren't the droids you're looking for". The only effective method against rootkits is either a.) disable lkm's (not an option for everyone) and b.) An email gets sent to you anytime a module gets loaded/unloaded. Option b won't prevent the root kit from being loaded, but it will let you know about it.

  2. By Bruj0 () on

    You mean something like this

  3. By Anonymous Coward () on

    If the machine has all/most important binaries/files with schg flags set and is in securelevel 2, with an mtree sha1digest snapshot sitting on a floppy, and usualy best practices are in use, is there any need for this ?

  4. By Jedi/Sector One () on

    Isn't checksumming one of the reason why extended attributes (man extattrl(8) on -current) were introduced?


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