Security Basics mailing list archives

Re: Bug in chkrootkit ?


From: Alex 'CAVE' Cernat <cave () cernat ro>
Date: Wed, 30 Jul 2003 19:52:13 +0300

"You have 4 process hidden for ps command" and the hint for a probably
installed "LKM Rootkit". So far, so good. "chkproc" with verbose
option enabled (-v) say:

[mw@zeus chkrootkit-0.38]# ./chkproc -v
PID 26194: not in ps output
PID 26195: not in ps output
PID 26196: not in ps output
PID 26197: not in ps output
You have 4 process hidden for ps command


try a better thing:
ls -l /proc/$pid/exe  - this command will give you the real path of the
executable 'name', which can be even '/usr/man/man1/xxx/whatever/named'
also you can try ls -l /proc/$pid/fd/  - list of file descriptors opened
by process $pid

i had a server cracked and chrootkit report me 2 process hidden; and
they we're on my system, hidden for ps and top, but not enough hidden
for absolute path
i'm not sure, but i believe that a lkm is clever enough (ie. very good
programmed), it can really 'wipe' a file/process/??? from the system, so
it's hard sometimes to diagnose your server

Alex

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