From: Crispin Cowan <crispin@immunix.com> Date: Sun, 17 Aug 2003 15:42:07 -0700 Shaun Clowes wrote: >I think it's generally accepted that homogenity breeds insecurity, in >which case it makes sense to try to be as different from everyone else >as possible even if that doesn't make it impossible for someone to break >you. > That is a commonly held view, but I would not say it is widely accepted. I certainly don't accept it. Heterogeneity increases survivability of the *species*, but does little to protect the individual . . . I don't think that stands up, at least not for digital species. I can run Apache on Linux/x86, for which tons of shellcode is available, or I can run the same version of Apache on Linux/sparc, for which much less is available, and exists within a smaller and more specialized community. For a member of a biological species, this would be tantamount to switching to an entirely different biochemistry at will, in order to become indigestible to the majority of predators (and making the Darwinian metaphor much harder to digest in the process). From this perspective, it is clear that choosing the "biochemistry" of Sparcs would protect me as an individual. At the very least, I can expect to have more time to patch my Sparc when a new vulnerability comes to light. . . . At most, you could say that running the most common system makes you somewhat more vulnerable to attack, and you should take that into consideration when planning your security. Yes; and it would be interesting (though probably difficult) to quantify that. Exploits are often cobbled together from several sources, so the size of an "exploit community" has a direct bearing on how quickly an exploit becomes available after a member of that community learns of an exploitable flaw. Perhaps the dependence of time to exploit on community size is even quadratic? If so, then heterogeneity benefits the whole ecological niche, by fragmenting exploit communities and therefore making them less efficient. So heterogeneity is really just security by obscurity, dressed up to sound pretty . . . Seems to me that obscurity is the *only* defence against exploits for unpublished/unpatched vulnerabilities that are spreading in the cracker community; if you can avoid being a target, by whatever means, then you are ahead of the game. Anyway, thank you for posting, and making me think. -- Bob Rogers http://rgrjr.dyndns.org/ P.S. to moderator: I am hoping that this has diverged sufficiently from the original "Buffer overflow prevention" thread to be worth approving . . .
