chkrootkit  0.55
About: chkrootkit is a shell script that checks system binaries for rootkit modification.
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                         chkrootkit V. 0.55

          Nelson Murilo <> (main author)
            Klaus Steding-Jessen <> (co-author)

          This program locally checks for signs of a rootkit.
         chkrootkit is available at:

                 No illegal activities are encouraged!
         I'm not responsible for anything you may do with it.

           This tool includes software developed by the
           DFN-CERT, Univ. of Hamburg (chklastlog and chkwtmp),
           and small portions of ifconfig developed by
           Fred N. van Kempen, <>.

 1. What's chkrootkit?

 chkrootkit is a tool to locally check for signs of a rootkit.  It

 * chkrootkit: a shell script that checks system binaries for
   rootkit modification.

 * ifpromisc.c: checks if the network interface is in promiscuous

 * chklastlog.c: checks for lastlog deletions.

 * chkwtmp.c: checks for wtmp deletions.

 * check_wtmpx.c: checks for wtmpx deletions.  (Solaris only)

 * chkproc.c: checks for signs of LKM trojans.

 * chkdirs.c: checks for signs of LKM trojans.

 * strings.c: quick and dirty strings replacement.

 * chkutmp.c: checks for utmp deletions.

 chkwtmp and chklastlog *try* to check for deleted entries in the wtmp
 and lastlog files, but it is *not* guaranteed that any modification
 will be detected.

 Aliens tries to find sniffer logs and rootkit config files.  It looks
 for some default file locations -- so it is also not guaranteed it
 will succeed in all cases.

 chkproc checks if /proc entries are hidden from ps and the readdir
 system call.  This could be the indication of a LKM trojan.  You can
 also run this command with the -v option (verbose).

 2. Rootkits, Worms and LKMs detected

 For an updated list of rootkits, worms and LKMs detected by
 chkrootkit please visit:

 3. Supported Systems

 chkrootkit has been tested on: Linux 2.0.x, 2.2.x, 2.4.x and 2.6.x,
 FreeBSD 2.2.x, 3.x, 4.x and 5.x, OpenBSD 2.x, 3.x and 4.x., NetBSD
 1.6.x, Solaris 2.5.1, 2.6, 8.0 and 9.0, HP-UX 11, Tru64, BSDI and Mac
 OS X.

 4. Package Contents




 5. Installation

 To compile the C programs type:

 # make sense

 After that it is ready to use and you can simply type:

 # ./chkrootkit

 6. Usage

 chkrootkit must run as root.  The simplest way is:

 # ./chkrootkit

 This will perform all tests.  You can also specify only the tests you
 want, as shown below:

 Usage: ./chkrootkit [options] [testname ...]
         -h                show this help and exit
         -V                show version information and exit
         -l                show available tests
         -d                debug
         -q                quiet mode
         -x                expert mode
         -r dir            use dir as the root directory
         -p dir1:dir2:dirN path for the external commands used by chkrootkit
         -n                skip NFS mounted dirs

 Where testname stands for one or more from the following list:

 aliens asp bindshell lkm rexedcs sniffer w55808 wted scalper slapper
 z2 chkutmp amd basename biff chfn chsh cron crontab date du dirname
 echo egrep env find fingerd gpm grep hdparm su ifconfig inetd
 inetdconf identd init killall ldsopreload login ls lsof mail mingetty
 netstat named passwd pidof pop2 pop3 ps pstree rpcinfo rlogind rshd
 slogin sendmail sshd syslogd tar tcpd tcpdump top telnetd timed
 traceroute vdir w write

 For example, the following command checks for trojaned ps and ls
 binaries and also checks if the network interface is in promiscuous

   # ./chkrootkit ps ls sniffer

 The `-q' option can be used to put chkrootkit in quiet mode -- in
 this mode only output messages with `infected' status are shown.

 With the `-x' option the user can examine suspicious strings in the
 binary programs that may indicate a trojan -- all the analysis is
 left to the user.

 Lots of data can be seen with:

   # ./chkrootkit -x | more

 Pathnames inside system commands:

   # ./chkrootkit -x | egrep '^/'

 chkrootkit uses the following commands to make its tests: awk, cut,
 egrep, find, head, id, ls, netstat, ps, strings, sed, uname.  It is
 possible, with the `-p' option, to supply an alternate path to
 chkrootkit so it won't use the system's (possibly) compromised
 binaries to make its tests.

 To use, for example, binaries in /cdrom/bin:

   # ./chkrootkit -p /cdrom/bin

 It is possible to add more paths with a `:'

   # ./chkrootkit -p /cdrom/bin:/floppy/mybin

 Sometimes is a good idea to mount the disk from a compromised machine
 on a machine you trust.  Just mount the disk and specify a new
 rootdir with the `-r' option.

 For example, suppose the disk you want to check is mounted under
 /mnt, then:

   # ./chkrootkit -r /mnt

 7. Output Messages

 The following messages are printed by chkrootkit (except with the -x
 and -q command options) during its tests:

   "INFECTED": the test has identified a command probably modified by
   a known rootkit;

   "not infected": the test didn't find any known rootkit signature.

   "not tested": the test was not performed -- this could happen in
   the following situations:
     a) the test is OS specific;
     b) the test depends on an external program that is not available;
     c) some specific command line options are given. (e.g. -r ).

   "not found": the command to be tested is not available;

   "Vulnerable but disabled": the command is infected but not in use.
   (not running or commented in inetd.conf)

 8. A trojaned command has been found.  What should I do now?

 Your biggest problem is that your machine has been compromised and
 this bad guy has root privileges.

 Maybe you can solve the problem by just replacing the trojaned
 command -- the best way is to reinstall the machine from a safe media
 and to follow your vendor's security recommendations.

 9. Reports and questions

 Please send comments, questions and bug reports to and

 A simple FAQ and Related information about rootkits and security can
 be found at chkrootkit's homepage,



 11. ChangeLog

 02/20/1997 - Initial release
 02/25/1997 - Version 0.4, formal testing.
 03/30/1997 - Version 0.5, suspect files routine added.
 06/11/1997 - Version 0.6, minor fixes and Debian compatibility.
 06/24/1997 - Version 0.7, FreeBSD compatibility fixed.
 08/07/1997 - Version 0.8, yet another FreeBSD compatibility and
                           RedHat PAM fixed.
 04/02/1998 - Version 0.9, new r00tkits versions support.
 07/03/1998 - Version 0.10, another types of r00tkits supported.
 10/15/1998 - Version 0.11, bug found by Alberto Courrege Gomide fixed.
 11/30/1998 - Version 0.12, lrk4 support added.
 12/26/1998 - Version 0.13, minor fixes for Red Hat and glibc users.
 06/14/1999 - Version 0.14, Sun/Solaris initial support added.
 04/29/2000 - Version 0.15, lrk5 features added and minor fixes.
 07/09/2000 - Version 0.16, new r00tkits types support and contrib patches.
 09/16/2000 - Version 0.17, more contrib patches, rootkit types and
                            Loadable Kernel Modules (LKM) trojan checking
 10/08/2000 - Version 0.18, new rookits types support and many bug fixes.
 12/24/2000 - Version 0.19, -r, -p, -l options added.  ARK support
                            added.  Some bug fixes.
 01/18/2001 - Version 0.20, Ramen Worm and latest t0rnkit detection,
                            temporay check for promisc mode disabled
                            on Solaris boxes.
 01/19/2001 - Version 0.21, Corrects a bug in the Ramen Worm detection.
 01/26/2001 - Version 0.22, chklastlog core dump bug fixed, login and
                            bindshell false positives fixed, cron test
 03/12/2001 - Version 0.23, lrk6, rh[67]-shaper, RSHA and Romanian
                            rootkit detection.  Test for shell history
                            file anomalies.  More ports added to the
                            bindshell test.
 03/15/2001 - Version 0.23a fixes a bug found in the cron and
                            bindshell tests.

 03/22/2001 - Version 0.30  lots of new tests added.  RK17 and Lion
                            Worm detection.
 04/07/2001 - Version 0.31  new tests: gpm, rlogind, mgetty.  Adore
                            Worm detection.  Some bug fixes.
 05/07/2001 - Version 0.32  t0rn v8, LPD Worm, kenny-rk and Adore LKM
                            detection. Some Solaris bug fixes.
 06/02/2001 - Version 0.33  new tests added.  ShitC, Omega and Wormkit
                            Worm detection.  dsc-rootkit detection.
                            Some bug fixes.
 09/19/2001 - Version 0.34  new tests added.  check_wtmpx.c added.
                            Ducoci rootkit and x.c Worm detection.
                            `-q' option added.
 01/17/2002 - Version 0.35  tests added: lsof and ldsopreload.
                            strings.c added.  Ports added to the
                            bindshell test.  RST.b, duarawkz, knark
                            LKM, Monkit, Hidrootkit, Bobkit, Pizdakit,
                            t0rn v8.0 (variant) detection.
 06/15/2002 - Version 0.36  test added: w.  chkproc.c additions.
                            Showtee, Optickit, T.R.K, MithRa's
                            Rootkit, George and SucKIT detection.
 09/16/2002 - Version 0.37  tests added: scalper and slapper.
                            Scalper Worm, Slapper Worm, OpenBSD rk
                            v1, Illogic and SK rootkit detection.
                            chklastlog.c and chkproc.c improvements.
                            Small chkrootkit bug fix.
 12/20/2002 - Version 0.38  chkdirs.c added.  chkproc.c improvements.
                            slapper B, sebek LKM, LOC, Romanian
                            rootkit detection.  new test added: trojan
                            tcpdump.  Minor bug fixes in the
                            chkrootkit script.
 01/30/2003 - Version 0.39  chkdirs.c and chkproc.c fixes.  bug fixes
                            in the chkrootkit script.  (more) Slapper
                            variants detection.
 04/03/2003 - Version 0.40  chkproc.c fixes.  Tru64 support. small
                            corrections in chkrootkit.  New test
                            added: init.  New rootkits detected: shv4,
                            Aquatica, ZK.
 06/20/2003 - Version 0.41  chkproc.c fixes.  New test added: vdir.
                            New worms detected: 55808.A and TC2. New
                            rootkits detected: Volc, Gold2, Anonoying,
                            Suckit (improved), ZK (improved).  Minor
 09/12/2003 - Version 0.42  BSDI support for chkdirs.c.  chkproc.c
                            fix.  New rootkit detected: ShKit.
                            ifpromisc test fixed for Linux 2.4.x
                            kernels. corrections for the -r option.
                            FreeBSD 5.x support.  HPUX correction.
                            Extra "\n" removed from chklastlog.c
 09/18/2003 - Version 0.42a Bug fix release.
 09/20/2003 - Version 0.42b Bug fix release.
 12/27/2003 - Version 0.43  C++ comments removed from chkproc.c.  New
                            rootkits detected: AjaKit and zaRwT.  New
                            CGI backdoors detected.  ifpromisc.c:
                            better detection of promisc mode on newer
                            Linux kernels.  New command line option
                            (-n) to skip NFS mounted dirs. Minor bug
 09/01/2004 - Version 0.44  chkwtmp.c: del counter fixed. chkproc.c:
                            better support for Linux threads.  New
                            rootkit detected: Madalin.  Lots of minor
                            bug fixes.
 02/22/2005 - Version 0.45  chkproc.c: better support for Linux
                            threads.  New rootkit detected: Fu,
                            Kenga3, ESRK.  New test: chkutmp.  -n
                            option improvement.  Minor bug fixes.
 10/26/2005 - Version 0.46  chkproc.c: more fixes to better support
                            Linux threads. chkutmp.c: improved
                            execution speed.  chkwtmp.c: segfault
                            fixed.  New rootkit detected: rootedoor.
                            Mac OS X support added.  Minor bug fixes.
 10/28/2005 - Version 0.46a chkproc.c: bug fix for FreeBSD: chkproc
                            was sending a SIGXFSZ (kill -25) to init,
                            causing a reboot.
 10/10/2006 - Version 0.47  chkproc.c: bug fixes, use of getpriority(),
                            Enye LKM detected. chkrootkit: crontab
                            test, Enye LKM and Lupper.Worm detected,
                            minor bug fixes.
 12/17/2007 - Version 0.48  new tests: common SSH brute force
                            scanners, suspicious PHP files.  Enhanced
                            tests: login, netstat, top, backdoor.
                            Minor bug fixes.
 09/30/2009 - Version 0.49  new tests: Mac OS X OSX.RSPlug.A.  Enhanced
                            tests: suspicious sniffer logs, suspicious
                            PHP files, shell history file anomalies.
                            Bug fixes in chkdirs.c, chkproc.c and

 04/30/2014 - Version 0.50 new tests: linuxrootkit-AMD-64-sound 
                           Operation Windigo ssh backdoor detection 
			   Minor bug fixes

 10/13/2016 - Version 0.51 Mumblehard backdoor/botnet detection 
			   Linux.Xor.DDoS Malware
                           Malicious TinyDNS detection 
                           Backdoors.Linux.Mokes.a detection 
			   Minor bug fixes 

 13/03/2017 - Version 0.52 Linux.Proxy.10 detection 
              strings.c & chkutmp.c bug fixes

 01/25/2019 - Version 0.53 Rocke Monero Miner detection
                          Added ss support
	                  ifconfig.c bug fixes 
                          Minor bug fixes 

 12/24/2020 - Version 0.54 PWNLNX4 and 6 Rootkits detection
			BTRFS bug fix 
			Fedora bug fix
			Bug fix release

 06/10/2021 - Version 0.55 Umbreon Linux Rootkit detection 
			Kinsing.A Backdoor 
			RotaJakito Backdoor 
			Minor bug fixes 

 -------------- Thx for using chkrootkit ----------------