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-   -   Weird entries in log file (http://www.linuxquestions.org/questions/linux-security-4/weird-entries-in-log-file-105149/)

KennyK 10-17-2003 10:20 AM

Weird entries in log file
 
I see these entries in here and am not sure what they are. Does anyone know what this is?
/var/log/secure


Oct 14 14:57:01 server xinetd[2208]: START: sgi_fam pid=19886 from=<no address>
Oct 14 15:39:34 server usermod[20321]: change user `gdm' shell from `/sbin/nologin' to `/sbin/nologin'
Oct 14 15:39:47 server usermod[20359]: change user `mailman' GID from `41' to `41'
Oct 14 15:39:47 server usermod[20359]: change user `mailman' shell from `/bin/false' to `/sbin/nologin'
Oct 14 15:41:19 server sshd[2194]: Received signal 15; terminating.
Oct 14 15:41:22 server sshd[20688]: Server listening on 0.0.0.0 port 22.

Any help would be great.

Regards

jayjwa 10-17-2003 05:03 PM

You sure you the only one that's got the root password? Either someone else is also doing things that normally require root privilleges or you have the worst memory to date in history!I'm not familiar with RH, but ain't sgi_fam the file alteration monitor? I'd say sometime fishy is up. If you have an md5sum of sshd, now may be the time to check it, just for hell. md5sum the top trojan'ed files. I know there's a sshd trojan going around right now. That plus the file alter. w/no address + sshd being shutdown & restarted looks like the start of trouble to me. I keep a hidden file with md5sums of the most popular trojaned apps + the ones I would hate for someone to trojan. That way I can tell if something is changed, by either virus/worm, trojan, bad users, whatever- without having to run a full service like tripwire, which would surely be deactivated by a competent cracker anyway upon breach of system.
I'd gather some more info, keep an eye out, and maybe set a few intrustion detection traps. Then watch for action if it appears that nothing has really occured, based on the log evidence you have already.

-jayjwa

KennyK 10-17-2003 06:07 PM

This is fishy. It looks like this happened the same day that I got the DSL hooked up. But here are a few things that make me scratch my head.

1. This box has always benn behind a firewall.

2. As soon as I got the DSL hooked up, I applied all of the patches available.

I will have to check this out some more and see what I can come up with. Thanks for your reply, and anyones elses thoughts would be welcome.

Regards

jayjwa 10-17-2003 07:20 PM

What about the other logs- wtmp acct? Anything in lastlog, dmesg, syslog, xinetd.log, xinetd.msg? FW logs? What ports are in use; services?

chort 10-17-2003 08:28 PM

Check the README files associated with the patches you installed. Some of them may have changed system user's shell to /sbin/nologin as part of a security patch.

SSH exiting and resarting was probably due to applying the fixes for the memory management flaws in OpenSSH.


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