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Re: chkrootkit infected ports 2881



Thomas Preud'homme on 04/08/08 13:39, wrote:
Monday 04 August 2008, Adam Hardy wrote :
Thomas Preud'homme on 04/08/08 11:48, wrote:
Le lundi 4 août 2008, Adam Hardy a écrit :
Adam Hardy on 03/08/08 14:13, wrote:
My webserver system is actually a UML slice of a system at
memset.co.uk and all it does is run Apache Tomcat and sshd and
the stuff from memset - I thought it was pretty safe until I came
back today and found my nightly email report from chkrootkit
said:

The following suspicious files and directories were found:
/lib/init/rw/.ramfs

INFECTED (PORTS:  2881)

The .ramfs started appearing when I upgraded chkrootkit, so I
never worried about it, but Friday night's INFECTED alert was a
slap in the face with a wet fish. Saturday night's report went
back to normal - no mention of the port.

I scanned it from grc.com/x/portprobe and it came back as closed.

The only mention I can find in the logs is:

root@hardyaa1:~# grep 2881 /var/log/*
/var/log/setuid.today:
    2881   660   1 root       disk               0 Wed Apr 30
11:32:37 2008 /dev/rd/c1d30
r

and that's a PID, not a port, right?

So how bad does this look? Should I clean the system? If it is
rooted, how can I tell what the security flaw was? My password at
that point (since changed) was CE0dff2*£ so if it was a brute
force attack, then wow, they did well.
I talked to the support at the hosting company and they looked at
the system and said they couldn't see anything wrong with it - but
they can re-image it for me which normally costs a fee.

Is it worth re-imaging my system and re-installing everything?

I still have no idea what chkrootkit means when it says a port is
infected.


Adam
I don't think it's that important. chkrootkit seems a little
hazardous since there was a bug about chkrootkit killing a random
process (in fact one of its test was sending a signal to process
12345, this bug has been corrected).

I think a good anti-rootkit should be launched from another system
to be sure it's not deactivated by a smart rootkit.
Hopefully that is simpler than it sounds! What anti-rootkit are you
thinking of? I use chkrootkit and rkhunter.

Unfortunetely I haven't any reference but hoping a rootkit on your computer being launched once a day will protect you is like hoping an anti-virus will protect you even if a smart virus infect your computer between 2 launch. It's better than nothing but I don't think it's sufficient.

Yes, you are right, and I have been too slack to get around to changing it. I am looking at installing tripwire (after a fresh install) to be able to check up what is going on after the fact.




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