Hunting the root kits


Within Linux mailing list there has been post on hacked Linux box. We have recommended root kit scan. There are two important tools on Linux now, rkhunter and chkrootkit.

[root@box ~]# chkrootkit
ROOTDIR is '/'
Checking 'amd'... not found
Checking 'basename'... not infected
Checking 'biff'... not found
Checking 'chfn'... not infected
Checking 'chsh'... not infected
Checking 'cron'... not infected
Checking 'crontab'... not infected
Checking 'date'... not infected
Checking 'du'... not infected
Checking 'dirname'... not infected
Checking 'echo'... not infected
Checking 'egrep'... not infected
Checking 'env'... not infected
Checking 'find'... not infected
Checking 'fingerd'... not found
Checking 'gpm'... not infected
Checking 'grep'... not infected
Checking 'hdparm'... not infected
Checking 'su'... not infected
Checking 'ifconfig'... not infected
Checking 'inetd'... not found
Checking 'inetdconf'... not found
Checking 'identd'... not found
Checking 'init'... not infected
Checking 'killall'... not infected
Checking 'ldsopreload'... not infected
Checking 'login'... not infected
Checking 'ls'... not infected
Checking 'lsof'... not infected
Checking 'mail'... not infected
Checking 'mingetty'... not infected
Checking 'netstat'... not infected
Checking 'named'... not found
Checking 'passwd'... not infected
Checking 'pidof'... not infected
Checking 'pop2'... not found
Checking 'pop3'... not found
Checking 'ps'... not infected
Checking 'pstree'... not infected
Checking 'rpcinfo'... not infected
Checking 'rlogind'... not found
Checking 'rshd'... not found
Checking 'slogin'... not infected
Checking 'sendmail'... not infected
Checking 'sshd'... not infected
Checking 'syslogd'... not infected
Checking 'tar'... not infected
Checking 'tcpd'... not infected
Checking 'tcpdump'... not infected
Checking 'top'... not infected
Checking 'telnetd'... not found
Checking 'timed'... not found
Checking 'traceroute'... not infected
Checking 'vdir'... not infected
Checking 'w'... not infected
Checking 'write'... not infected
Checking 'aliens'... no suspect files
Searching for sniffer's logs, it may take a while... nothing found
Searching for HiDrootkit's default dir... nothing found
Searching for t0rn's default files and dirs... nothing found
Searching for t0rn's v8 defaults... nothing found
Searching for Lion Worm default files and dirs... nothing found
Searching for RSHA's default files and dir... nothing found
Searching for RH-Sharpe's default files... nothing found
Searching for Ambient's rootkit (ark) default files and dirs... nothing found
Searching for suspicious files and dirs, it may take a while...
/usr/lib/perl5/vendor\_perl/5.8.5/i386-linux-thread-multi/auto/Razor2/Preproc/deHTMLxs/.packlist /usr/lib/perl5/vendor\_perl/5.8.5/i386-linux-thread-multi/auto/mod\_perl/.packlist /usr/lib/perl5/5.8.5/i386-linux-thread-multi/.packlist

Searching for LPD Worm files and dirs... nothing found
Searching for Ramen Worm files and dirs... nothing found
Searching for Maniac files and dirs... nothing found
Searching for RK17 files and dirs... nothing found
Searching for Ducoci rootkit... nothing found
Searching for Adore Worm... nothing found
Searching for ShitC Worm... nothing found
Searching for Omega Worm... nothing found
Searching for Sadmind/IIS Worm... nothing found
Searching for MonKit... nothing found
Searching for Showtee... nothing found
Searching for OpticKit... nothing found
Searching for T.R.K... nothing found
Searching for Mithra... nothing found
Searching for LOC rootkit... nothing found
Searching for Romanian rootkit... nothing found
Searching for HKRK rootkit... nothing found
Searching for Suckit rootkit... nothing found
Searching for Volc rootkit... nothing found
Searching for Gold2 rootkit... nothing found
Searching for TC2 Worm default files and dirs... nothing found
Searching for Anonoying rootkit default files and dirs... nothing found
Searching for ZK rootkit default files and dirs... nothing found
Searching for ShKit rootkit default files and dirs... nothing found
Searching for AjaKit rootkit default files and dirs... nothing found
Searching for zaRwT rootkit default files and dirs... nothing found
Searching for Madalin rootkit default files... nothing found
Searching for Fu rootkit default files... nothing found
Searching for ESRK rootkit default files... nothing found
Searching for rootedoor... nothing found
Searching for ENYELKM rootkit default files... nothing found
Searching for common ssh-scanners default files... nothing found
Searching for suspect PHP files... nothing found
Searching for anomalies in shell history files... nothing found
Checking 'asp'... not infected
Checking 'bindshell'... INFECTED (PORTS:  465)
Checking 'lkm'... chkproc: nothing detected
chkdirs: nothing detected
Checking 'rexedcs'... not found
Checking 'sniffer'... eth0: not promisc and no PF\_PACKET sockets
eth0:0: not promisc and no PF\_PACKET sockets
Checking 'w55808'... not infected
Checking 'wted'... chkwtmp: nothing deleted
Checking 'scalper'... not infected
Checking 'slapper'... not infected
Checking 'chkutmp'...  The tty of the following user process(es) were not found
in /var/run/utmp !
! RUID          PID TTY    CMD
! root        19564 pts/0  -bash
! root        20746 pts/0  screen -DRU
chkutmp: nothing deleted
Checking 'OSX_RSPLUG'... not infected

Wow! It seems we have box chrooted.

Checking 'bindshell'... INFECTED (PORTS:  465)

Something is listening on 465 port, we have to find out more.

[root@box ~]# netstat -lnp | grep 465
tcp        0      0 0.0.0.0:465                 0.0.0.0:\*                   LISTEN      7624/master
[root@box ~]# fuser -vn tcp 465
here: 465

                     USER        PID ACCESS COMMAND
465/tcp              root       7624 f....  master

So, this is postfix running on port 465, providing SMTPS access. :)