Re: Questions = Thanks

From: Devdas Bhagat (devdasat_private)
Date: Wed Nov 21 2001 - 22:17:06 PST

  • Next message: Marco Slaviero: "More ssh attempts"

    On 22/11/01 00:18 +0100, Pascal Nobus wrote:
    > ----- Original Message -----
    > From: "Ihsahn Diablo" <traktopikaat_private>
    > 
    > >   So i have one more thing to ask you: to give me some good links about
    > what
    > > to do after a break or what to do if somebody is in the middle of an
    > atack.
    > 
    > boot your server up in single user mode
    > enter these commands
    > rpm -qa|sed "s/^/rpm --verify /g" > /root/verify-rpms
    > chmod +x /root/verify-rpms
    > /root/verify-rpms > /root/verify-results
    And your attacker has modified the online RPM database to give the new
    md5sums :).
    You can trust *nothing* on the cracked system. Check from an offline
    database. Make sure you have recent tripwire backups, and check those
    from a good known-to-be-correct database against the current ststus of
    the systems. Compare md5sums of every file with the ones on  a known to
    be clean system. (Just in case a LKM has been installed which catches
    open, and misses stat/read or whatever else).
    
    > wait for this list to complete
    > 
    > if you see files like /bin/ls, /bin/ps, /bin/login, /etc/pam.d/login,
    > /etc/pam.d/passwd, /etc/rc.d/rc.sysinit, /dev/*, /etc/services,
    > /usr/bin/find
    > showing up in this list then it's very likely you have been hacked into
    > 
    > you can determine which rpm each of these files came from and reinstall
    > the RPM for them from a secure media (Red Hat 6.2 CDROM) via
    Very bad advice. Format, patch and restore the data from backups.
    Harden, then bring the machine online.
    You can *never* trust a machine which was once broken into.
    
    Devdas Bhagat
    
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