Re: Irix logs + su

From: pmwsat_private
Date: Mon Dec 21 1998 - 03:26:27 PST

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    Subject: Re: Irix tape devices + logs + su
    
    hi,
    i hope this is no grey bearded stuff ;)
    
    On Dec 18,  6:05pm, Valdis.Kletnieksat_private wrote:
    > Subject: Re: Irix tape devices + logs + su
    > >  Also, /var/adm/SYSLOG contains the failed login names (even if they
    > > don't exist) and by default, this file is forced to be mode 644
    (root's
    > > crontab will take care for this, when rotating the logs).
    >
    > This can be an issue.
    >
    there is a much more funny 'feature': if you add an user via
    addUserAccount this action is logged in SYSLOG including the (crypted) password (seen on
    a origin 2000). to me, this makes /etc/shadow rather useless. on my machines
    i cannot reproduce this behavior. is there anybody who has seen this
    before??
    
    > >  Finaly, when using su, the user's .cshrc will be executed with
    > > privileges of the target user (if the su is succesful). For example,
    > > if user nobody has a cp /bin/sh /tmp; chmod 6755 /tmp/sh in his .cshrc
    > > and he use su to become root, a rootshell will be available in /tmp :)
    > > This is valid only for succesfull su's
    >
    > So?  They're root, and they could do that *anyhow*. No exposure here.
    >
    > Now, if the user can trick the sysadmin into su'ing and running the
    > user's .cshrc *instead* of the sysadmin's, that's more interesting.
    if yo read the su manpages it goes like:
    ...
         sh(1).  If the first argument to su is a -, the environment is
    changed to
         what would be expected if the user actually logged in as the
    specified
         user.  This is done by invoking the program used as the shell with an
         arg0 value whose first character is -, thus causing the system's
    profile
         (/etc/profile) and then the specified user's profile (.profile in the
    new
         HOME directory) to be executed.
    ...
    and this works as expected: if you add the - option nothing evil happens.
    otherwise you're lost ;) (at my machines at least...)
    > >-- End of excerpt from Valdis.Kletnieksat_private
    
    merry x-mas,
    philipp
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