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Re: Buffer Overflows: A Summary
From: mcguire () CS UTEXAS EDU (Tommy Marcus McGuire)
Date: Fri, 2 May 1997 10:18:57 -0500
Bill Trost <trost () CLOUD RAIN COM> wrote:
Aleph One writes: It was suggested that the kernel should check in the exec system call to determine if a shell was being executed.... This path of thinking doe
s
lead to an interesting defense that I believe would be of great use and should be implemented. Most daemons and utilities will not exec a progra
m.
Most will simply fork. In such cases a system call that disabled any further calls to exec would stop all exploits that attempted to use the exec system call.... That's an interesting idea, but note that the attacker need not call "exec", that's just the easiest approach. Given access to "open", "write" and "chmod
"
or "umask" is probably equivalent, it just takes longer to write the exploit. And while I can see giving up a variety of system calls to enhance security, "open" and "write" are not among them. (-:
Oddly enough, we had a talk here in the CS department earlier this week by Mootaz Elnozahy from Carnegie Mellon who suggested the idea of writing a system call pattern associated with a security sensitive program. The pattern would specify which calls would be used, with what arguments, and in what order, etc. The kernel could check the program's execution, and if the kernel detects a problem, it drops the program into a secure mode where the attacker continues to get responses like the attack is succeeding, but can't actually do any damage. A neat idea, although I don't know how practical it would be. Tommy McGuire
Current thread:
- Re: Buffer Overflows: A Summary Bill Trost (May 01)
- Re: Buffer Overflows: A Summary Tommy Marcus McGuire (May 02)
- Re: Buffer Overflows: A Summary Gene Spafford (May 02)
- Windows NT 4.0 SAM hotfix Aleph One (May 02)
- Re: Buffer Overflows: A Summary Lamont Granquist (May 03)
- Solaris lpNet & temp files (exploit) Chris Sheldon (May 03)
- Re: Solaris lpNet & temp files (exploit) Casper Dik (May 07)
- A bug in Elm fflush (May 04)
- Re: A bug in Elm Larry Schwimmer (May 04)
- Hole in the KDE desktop Alan Cox (May 05)
- A vulnerability in Lynx (all versions) fflush (May 05)
- Re: A vulnerability in Lynx (all versions) Theo de Raadt (May 05)
- Re: Buffer Overflows: A Summary Tommy Marcus McGuire (May 02)