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kernel.org status: hints on how to check your machine for intrusion

kernel.org status: hints on how to check your machine for intrusion

Posted Oct 4, 2011 22:24 UTC (Tue) by nls (guest, #80623)
In reply to: kernel.org status: hints on how to check your machine for intrusion by RomLWN
Parent article: kernel.org status: hints on how to check your machine for intrusion

I ran chkrootkit and got several "5 deletion(s) between...".

I use Fedora 15. I have two other systems running Fedora 14 which do not indicate deletions from wtmp.

I think this problem may be a bug. A search of my logs did not indicate any funny business (intrusion). I did find a very strong correlation between the time of the deletions and shutting down the system.

I compared the times of the "deletion(s)" and the /var/log/message* files by greping the rsyslogd messages associated with shutdown.

$ su -c "grep rsyslogd /var/log/messages | grep exiting"

I would be very interested if you were to find the same correlation.

I think there may be corruption at the end of wtmp at shutdown.

It makes no sense to me for a bad-hacker to try to cover his tracks at shutdown.


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kernel.org status: hints on how to check your machine for intrusion

Posted Oct 5, 2011 17:22 UTC (Wed) by nls (guest, #80623) [Link]

I did a fresh install of FC15 on another system. I installed chkrootkit. I rebooted. I ran chkrootkit. I got one wted message "5 deletion(s)". It appears during shutdown wtmp is being corrupted.

Checking `wted'... 5 deletion(s) between Wed Oct 5 12:43:57 2011 and Wed Oct 5 12:44:09 2011

[admin@opusrex ~]$ su -c "grep rsyslogd /var/log/messages | grep exiting"
Password:
Oct 5 12:44:06 opusrex rsyslogd: [origin software="rsyslogd" swVersion="5.8.5" x-pid="1023" x-info="http://www.rsyslog.com"] exiting on signal 15.

I will report bug to Fedora.

kernel.org status: hints on how to check your machine for intrusion

Posted Oct 6, 2011 9:46 UTC (Thu) by jwakely (subscriber, #60262) [Link]

I get dozens of "wted deletions" with chkrootkit on F15, which all coincide with shutting down. I also get a warning about X running without an entry in utmp. I was considering reporting it to bugzilla too, but I'll CC myself on your bugzilla report

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