Re: [OT] Rootkit queston

From: Albert Cahalan
Date: Tue Dec 02 2003 - 18:44:20 EST

> I've been paranoid after I heard that the debian project
> got "rootkitted", I ran chkrootkit, and it said that
> it's possible that I have a LKM rootkit installed, but
> the website told me that it's possible that the LKM test
> gives wrong information with recent kernels (Running 2.4.22
> now).
> These processes "were hidden from ps command":
> root 0 0.0 0.0 0 0 ? SWN Oct28 0:01 [ksoftirqd CPU0]
> root 0 0.0 0.0 0 0 ? SW Oct28 4:27 [kswapd]
> root 0 0.0 0.0 0 0 ? SW Oct28 0:00 [bdflush]
> root 0 0.0 0.0 0 0 ? SW Oct28 0:01 [kupdated]
> They seem to have PID 0, is this normal?

Yes and no. This is a kernel bug that trips up libproc.

The first number in a /proc/*/stat file should match
the Tgid number in the /proc/*/status file it goes with.
This is the POSIX PID. (note: NOT the "Pid" value)

Early 2.4.xx kernels didn't try to report this in
the /proc/*/status files at all, so libproc would
use the /proc/*/stat data instead. Recent 2.4.xx
kernels report the data. It seems that the data is
left uninitialized for the built-in kernel tasks.

Though there will be a work-around in future libproc
code, the 2.4.xx kernel ought to get fixed anyway.

> Do my system have a rootkit installed?

I don't think so.

> If it does, how do I remove it?

Boot from CD-ROM and reinstall the OS.

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