Re: SSH allows deletion of other users files...

From: Dan Astoorian (djastat_private)
Date: Mon Jun 04 2001 - 14:11:34 PDT

  • Next message: sarnoldat_private: "Re: SSH allows deletion of other users files..."

    On Mon, 04 Jun 2001 12:08:26 EDT, Jason DiCioccio writes:
    > 
    > Also: SSH Version OpenSSH_2.3.0 greenat_private 20010321 -- That comes 
    > with FreeBSD 4.3-STABLE
    > is not vulnerable at first glance.  It does not appear to use /tmp files 
    > as yours does and therefore is not vulnerable.
    
    My testing indicates that OpenSSH 2.3.0p1 *is* vulnerable if X11
    forwarding is permitted.  However, the /tmp/ssh-*/cookie file is not
    created/removed unless X11 forwarding is enabled for the connection.
    
    Note that some vendors ship OpenSSH with X11 forwarding disabled by
    default *in the client*, which may be why you did not observe the
    problem on FreeBSD.  Be sure to use the "-X" option to ssh to enable X11
    forwarding in the client, and make sure you're testing from a client
    where $DISPLAY is pointing at an X server.  The $XAUTHORITY environment
    variable will give the pathname to the file which is unlink()'d when the
    connection is closed.
    
    (For those who merely tried the literal commands submitted by
    zen-parseat_private, note also that the directory to be 'rm -r'd  isn't
    simply "/tmp/ssh-XXW9hNY9", but will depend on the value of that
    XAUTHORITY variable; it will be different for each ssh connection.)
    
    -- 
    Dan Astoorian               People shouldn't think that it's better to have
    Sysadmin, CSLab             loved and lost than never loved at all.  It's
    djastat_private        not, it's better to have loved and won.  All
    www.cs.toronto.edu/~djast/  the other options really suck.    --Dan Redican
    



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