Re: Security Problem in MH 6.8.4

From: Philip Guenther (guentherat_private)
Date: Tue Jan 20 1998 - 11:37:14 PST

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    In response to the security hole in MH's inc program,
    mparsonat_private writes:
    >How about:
    >
    >Remove suid bit from inc.
    
    I'll second this with the note that inc only needs to be setuid for
    RPOP, a non-standard POP authentication method which uses
    rlogin/rsh-like authentication via ruserok().  We all know how secure
    _that_ is, so losing that functionality might be considered a feature.
    Of course, you should check to make sure your popserver doesn't support
    RPOP to catch that hole.
    
    
    >Instead, use popclient to retrieve mail and procmail/rcvstore to deliver
    >the messages into the MH mailboxes.  This still allows users to use inc
    >to suck in mbox format mailboxes.
    
    You can still do POP with either username/password or APOP authentication
    with a non-setuid inc -- you just have to type your password each time.
    
    
    >The popclient package is also installed by default with RedHat (at least it
    >was with 4.2, I haven't installed 5.0 yet).
    >
    >> MH also installs another suid-program: msgchk. It's also posible to get a
    >> Segmentation fault whith the same option, but I haven't been able to exploit
    >> it. I have worked on it quite a few. Could someone probe it a little deeper??
    
    Once again, RPOP is reason behind the setuid bit being on.  Torch it.
    
    Redhat should be compiling MH without RPOP and overriding the
    installation commands that turn on the setuid bits on inc and msgchk.
    
    
    Philip Guenther
    
    ----------------------------------------------------------------
    Philip Guenther                 UNIX Systems and Network Administrator
    Internet: guentherat_private      Voicenet: (507) 933-7596
    Gustavus Adolphus College       St. Peter, MN 56082-1498
    



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