**-Unhide-**
               http://www.unhide-forensics.info

Unhide is a forensic tool to find hidden processes and TCP/UDP ports by rootkits / LKMs
or by another hiding technique.

// Unhide (unhide-linux or unhide-posix)
// -------------------------------------

Detecting hidden processes. Implements six main techniques

1- Compare /proc vs /bin/ps output

2- Compare info gathered from /bin/ps with info gathered by walking thru the procfs. ONLY for unhide-linux version

3- Compare info gathered from /bin/ps with info gathered from syscalls (syscall scanning).

4- Full PIDs space occupation (PIDs bruteforcing). ONLY for unhide-linux version

5- Compare /bin/ps output vs /proc, procfs walking and syscall. ONLY for unhide-linux version
   Reverse search, verify that all thread seen by ps are also seen in the kernel.

6- Quick compare /proc, procfs walking and syscall vs /bin/ps output. ONLY for unhide-linux version
  It's about 20 times faster than tests 1+2+3 but maybe give more false positives.

// Unhide_rb
// ---------

It's a back port in C language of the ruby unhide.rb

As the original unhide.rb, it is roughly equivalent to "unhide-linux quick reverse" but:
- it makes three tests less (kill, opendir and chdir),
- it only run /bin/ps once at start and once for the double check, this gives more false positives:
   short live processes are seen as hidden.
- also, its tests are less accurate (e.g. testing return value instead of errno),
- it doesn't scale well when max_PID number increases,
- processes are only identified by their exe link (unhide-linux also use cmdline and
  "sleeping kernel process" name),
- there's little protection against failures (failed fopen or popen by example),
- there's no logging capability.

On 32 bits system (with max_PID = 2^16) It is about 80 times quicker than "unhide-linux quick reverse"
On 64 bits system (with max_PID = 2^22) It is about 2 times quicker than "unhide-linux quick reverse"

// Unhide-TCP
// ----------

Identify TCP/UDP ports that are listening but not listed in sbin/ss or /bin/netstat.
It use two methods: 
- brute force of all TCP/UDP ports availables and compare with SS/netstat output.
- probe of all TCP/UDP ports not reported by netstat.

// Files
// -----

unhide-linux.c      -- Hidden processes, for Linux >= 2.6
unhide-linux.h

unhide-tcp.c        -- Hidden TCP/UDP Ports
unhide-tcp-fast.c
unhide-tcp.h

unhide-output.c     -- Common routines of unhide tools
unhide-output.h

unhide_rb.c         -- C port of unhide.rb (a very light version of unhide-linux in ruby)

unhide-posix.c      -- Hidden processes, for generic Unix systems (*BSD, Solaris, linux 2.2 / 2.4)
                       It doesn't implement PIDs brute forcing check yet. Needs more testing
                       Warning : This version is somewhat outdated and may generate false positive.
                                 Prefer unhide-linux.c if you can use it.

changelog           -- As the name implied log of the change to unhide

COPYING             -- License file, GNU GPL V3

LEEME.txt           -- Spanish version of this file

LISEZ-MOI.TXT       -- French version of this file

NEWS                -- Release notes

README.txt          -- This file

sanity.sh           -- unhide-linux testsuite file

TODO                -- Evolutions to do (any volunteers ?)

man/unhide.8        -- English man page of unhide

man/unhide-tcp.8    -- English man page of unhide-tcp

man/fr/unhide.8     -- French man page of unhide

man/fr/unhide-tcp.8 -- French man page of unhide-tcp

// Compiling
// ---------

 Build requires :
 --------------
   glibc-devel
   glibc-static-devel

 Requires :
 --------
   - unhide-tcp under linux :
      iproute2
      net-tools (for netstat)
      lsof
      psmisc (for fuser)
   - unhide-tcp under freeBSD :
      sockstat
      lsof
      netstat
   
   - unhide-linux, unhide-posix, unhide_rb :
      procps


IMPORTANT : Notes that, as a forensic tool, unhide is built statically as the host system libraries may be compromised and to avoid being fooled by a PRELINKing. 

If you ARE using a Linux kernel >= 2.6
      gcc -Wall -Wextra -O2 --static -pthread unhide-linux*.c unhide-output.c -o unhide-linux
      gcc -Wall -Wextra -O2 --static unhide-tcp.c unhide-tcp-fast.c unhide-output.c -o unhide-tcp
      gcc -Wall -Wextra -O2 --static unhide_rb.c -o unhide_rb
      ln -s unhide unhide-linux

Else (Linux < 2.6, *BSD, Solaris and other Unice)
      gcc --static unhide-posix.c -o unhide-posix
      ln -s unhide unhide-posix

// Using
// -----
You MUST be root to use unhide-linux and unhide-tcp.

Examples:
 # ./unhide-linux  -vo quick reverse
 # ./unhide-linux  -vom procall sys
 # ./unhide_rb

 # ./unhide-tcp  -flov
 # ./unhide-tcp  -flovs

// License
// -------

GPL V.3 (http://www.gnu.org/licenses/gpl-3.0.html)

// Greets
// ------

A. Ramos ([email protected]) for some regexps

unspawn ([email protected]) CentOS support

Martin Bowers ([email protected]) CentOS support

Lorenzo Martinez ([email protected]) Some ideas to improve and betatesting

Francois Marier ([email protected]) Author of the man pages and Debian support

Johan Walles ([email protected]) Find and fix a very nasty race condition bug

Jan Iven ([email protected]) Because of his great improvements, new tests and bugfixing

P. Gouin ([email protected]) Because of his incredible work fixing bugs and improving the performance

François Boisson for his idea of a double check in brute test

Leandro Lucarella ([email protected]) for the fast scan method and his factorization work for unhide-tcp

Nikos Ntarmos ([email protected]) for its invaluable help in the FreeBSD port of unhide-tcp and for packaging unhide on FreeBSD.

Fubin Zhang (zfb132 on GitHub) for reporting missing file in distribution tarball.

Buo-ren, Lin (brlin-tw in GitHub ; [email protected]) for fixing typo in Readme file

daichifukui ([email protected]) for pinpoint untranslated strings in GUI and fix them.