There are good reasons for extensible architectures. No changes are needed in this respect, we simply must restrict the scope of that extensibility at run-time to authorized add-on modules. Other programmers can make it easier for us to do so by adding some forensic profiling code to their programs, but this is not necessary to achieve substantially-improved practical control over the extensible code modules we allow to execute, including the ability to detect when arbitrary malicious code succeeds in overflowing a buffer and smashing the stack. Every path through third-party code that we have not profiled and explicitly authorized is simply denied by default, including portions of third-party code that are not harmful or of malicious foreign origin, so that in essence the defense says: "We will only allow code to execute that we have previously executed during forensic testing. Everything else is denied by default until we analyze its origin and intended function." Jason Coombs jasoncat_private -----Original Message----- From: Michael Wojcik [mailto:Michael.Wojcikat_private] Sent: Wednesday, February 05, 2003 10:43 PM To: BugTraq Cc: jasoncat_private; Nicholas Weaver Subject: RE: Observation on randomization/rebiasing... > From: Jason Coombs [mailto:jasoncat_private] > Sent: Wednesday, February 05, 2003 5:08 PM > A properly security-hardened binary DOES NOT require support > for arbitrary relocations, arbitrary dynamic library injection, > arbitrary code injection resulting in new execute paths defined at > run-time, and the type of programmability required by software > developers. Once code has been compiled and linked, even when that > code makes use of dynamic libraries, there is no longer any unknown. There are plenty of examples of programs and libraries that by design load and execute independently-developed code: browser plugins, ISAPI, and so forth. Leaving aside for the moment the question of whether this is a Good Thing, or whether it fits someone's definition of "a properly security-hardened binary", it's certainly a popular approach. The security community has not to date had much luck convincing users and programmers to adopt even its uncontroversial recommendations; I doubt you'll get any traction with this one. Michael Wojcik Principal Software Systems Developer, Micro Focus
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