unhide-posix

UNHIDE(8)                   System Manager's Manual                  UNHIDE(8)

NAME
       unhide -- forensic tool to find hidden processes

SYNOPSIS
       unhide [OPTIONS] TEST_LIST
       unhide-posix proc | sys

DESCRIPTION
       unhide  is  a forensic tool to find processes hidden by rootkits, Linux
       kernel modules or by other techniques.  It detects hidden processes us-
       ing six techniques.

OPTIONS
       Options are only available for unhide-linux not for unhide-posix.

       -d     Do a double check in brute test to avoid false positive.

       -f     Write a log file (unhide-linux.log) in the current directory.

       -h     Display help

       -m     Do  more  checks. As of 2012-03-17 version, this option has only
              effect for the  procfs,  procall,  checkopendir  and  checkchdir
              tests.
              Implies -v

       -r     Use alternate version of sysinfo check in standard tests

       -V     Show version and exit

       -v     Be  verbose,  display warning message (default : don't display).
              This option may be repeated more than once.

TEST_LIST
       The checks to do consist of one or more of the following tests.
       The standard tests are  the  aggregation  of  one  or  more  elementary
       test(s).

       Standard tests :

       The brute technique consists of bruteforcing the all process IDs.
       This technique is only available with version unhide-linux.

       The  proc  technique  consists  of  comparing  /proc with the output of
       /bin/ps.

       The procall technique combinates proc and procfs tests.
       This technique is only available with version unhide-linux.

       The procfs technique consists of comparing  information  gathered  from
       /bin/ps with information gathered by walking in the procfs.
       With -m option, this test makes more checks, see checkchdir test.
       This technique is only available with version unhide-linux.

       The  quick  technique combines the proc, procfs and sys techniques in a
       quick way. It's about 20 times faster but may  give  more  false  posi-
       tives.
       This technique is only available with version unhide-linux.

       The reverse technique consists of verifying that all threads seen by ps
       are also seen in procfs and by system calls. It is intended  to  verify
       that  a  rootkit has not killed a security tool (IDS or other) and make
       ps showing a fake process instead.
       This technique is only available with version unhide-linux.

       The sys technique  consists  of  comparing  information  gathered  from
       /bin/ps with information gathered from system calls.

       Elementary tests :

       The checkbrute technique consists of bruteforcing the all process IDs.
       This technique is only available with version unhide-linux.

       The  checkchdir  technique  consists  of comparing information gathered
       from /bin/ps with information gathered by making chdir() in the procfs.
       With the -m option, it also verify  that  the  thread  appears  in  its
       "leader process" threads list.
       This technique is only available with version unhide-linux.

       The  checkgetaffinity technique consists of comparing information gath-
       ered from /bin/ps with the result of call  to  the  sched_getaffinity()
       system function.
       This technique is only available with version unhide-linux.

       The  checkgetparam technique consists of comparing information gathered
       from /bin/ps with the result of call  to  the  sched_getparam()  system
       function.
       This technique is only available with version unhide-linux.

       The  checkgetpgid  technique consists of comparing information gathered
       from /bin/ps with the result of call to the getpgid() system function.
       This technique is only available with version unhide-linux.

       The checkgetprio technique consists of comparing  information  gathered
       from  /bin/ps with the result of call to the getpriority() system func-
       tion.
       This technique is only available with version unhide-linux.

       The checkRRgetinterval  technique  consists  of  comparing  information
       gathered  from  /bin/ps with the result of call to the sched_rr_get_in-
       terval() system function.
       This technique is only available with version unhide-linux.

       The checkgetsched technique consists of comparing information  gathered
       from /bin/ps with the result of call to the sched_getscheduler() system
       function.
       This technique is only available with version unhide-linux.

       The checkgetsid technique consists of  comparing  information  gathered
       from /bin/ps with the result of call to the getsid() system function.
       This technique is only available with version unhide-linux.

       The checkkill technique consists of comparing information gathered from
       /bin/ps with the result of call to the kill() system function.
       Note : no process is really killed by this test.
       This technique is only available with version unhide-linux.

       The checknoprocps technique consists of comparing  the  result  of  the
       call  to  each  of  the system functions. No comparison is done against
       /proc or the output of ps.
       This technique is only available with version unhide-linux.

       The checkopendir technique consists of comparing  information  gathered
       from  /bin/ps  with  information  gathered  by  making opendir() in the
       procfs.
       This technique is only available with version unhide-linux.

       The checkproc technique consists of comparing /proc with the output  of
       /bin/ps.
       This technique is only available with version unhide-linux.

       The  checkquick  technique combines the proc, procfs and sys techniques
       in a quick way. It's about 20 times faster but may give more false pos-
       itives.
       This technique is only available with version unhide-linux.

       The  checkreaddir  technique consists of comparing information gathered
       from /bin/ps with information gathered by making readdir() in /proc and
       /proc/pid/task.
       This technique is only available with version unhide-linux.

       The  checkreverse technique consists of verifying that all threads seen
       by ps are also seen in procfs and by system calls. It  is  intended  to
       verify that a rootkit has not killed a security tool (IDS or other) and
       make ps showing a fake process instead.
       This technique is only available with version unhide-linux.

       The checksysinfo technique consists of comparing the number of  process
       seen by /bin/ps with information obtained from sysinfo() system call.
       This technique is only available with version unhide-linux.

       The  checksysinfo2  technique  is  an alternate version of checksysinfo
       test.  It might (or not) work better on kernel patched for RT,  preempt
       or latency and with kernel that don't use the standard scheduler.
       It's also invoked by standard tests when using the -r option
       This technique is only available with version unhide-linux.

   Exit status:
       0      if OK,

       1      if a hidden or fake thread is found.

EXAMPLES
       Quicker test:
              unhide quick

       Quick test:
              unhide quick reverse

       Standard test:
              unhide sys proc

       Deeper test:
              unhide -m -d sys procall brute reverse

BUGS
       Report  unhide  bugs  on the bug tracker on sourceforge (http://source-
       forge.net/projects/unhide/)
       With recent versions of Linux kernel (> 2.6.33), the sysinfo  test  may
       report  false  positives.   It may be due to optimization in the sched-
       uler, the use of cgroup or even the use of systemd.   The  use  of  the
       PREEMPT-RT patch amplifies the occurrence of the problem.  This is cur-
       rently under investigation.

SEE ALSO
       unhide-tcp (8).

AUTHOR
       This manual page was written by Francois Marier francois@debian.org and
       Patrick Gouin.  Permission is granted to copy, distribute and/or modify
       this document under the terms of the GNU General Public  License,  Ver-
       sion 3 or any later version published by the Free Software Foundation.

LICENSE
       License   GPLv3+:  GNU  GPL  version  3  or  later  <http://gnu.org/li-
       censes/gpl.html>.
       This is free software: you are free  to  change  and  redistribute  it.
       There is NO WARRANTY, to the extent permitted by law.

Administration commands           March 2012                         UNHIDE(8)