Recent OpenBSD 2.8/2.9 Exploit - stephanie patched kernels unaffected

From: James Babiak (jfbabiakat_private)
Date: Thu Jun 21 2001 - 04:40:26 PDT

  • Next message: Matthew Potter: "Re: ISS Security Advisory: Wired-side SNMP WEP key exposure in 802.11b Access Points"

    In testing the recent obsd exploit by Georgi Guninski out, I have found out
    that my OpenBSD 2.8 box was not vulnerable. I have come to the conclusion
    that those boxes with the stephanie kernel patches by Mike Schiffman and doe
    are not vulnerable to this exploit, at least without modifying the exploit
    itself. My box has extremely anally granular file access control, however I
    ran this exploit using my account with full permissions, and I was in the
    tpe_adm group. I imagine that the symlink restrictions prevent the exploit
    from working.
    
    Workarounds:
    From what I read, the stephanie patches do not have hard link restrictions.
    However, on my box /tmp is its own partition (duh), therefore not allowing
    me to do a cross-device link. I don't have any obsd boxes without /tmp on
    its own partition to test this out, but it may be a workaround or at least a
    place to start.
    
    Re-write the exploit to not use the /tmp symlinks.
    
    I'm also sure there is some way to circumvent the symlink restrictions in
    place.
    
    In any case, I am working on a way around this, but at least with those
    patches in place, the exploit is "script-kiddie-proof." In other words, even
    Jeff King with his elite EXPN warez couldn't exploit it.
    
    For those not familiar to the Stephanie patch, you can read more about it
    and download it at:
    http://www.packetfactory.net/Projects/Stephanie/
    
    Congrats to route and doe for coming up with a patch to a hole not yet
    discovered =].
    
    -james
    



    This archive was generated by hypermail 2b30 : Fri Jun 22 2001 - 12:22:12 PDT