-Unhide-NG

IMPORTANT NOTE : Unhide-NG is not (yet) the updated version of Unhide. Unhide-NG is a lab project that may replace Unhide in an indeterminate future. For new version of unhide, check https://github.com/YJesus/Unhide/releases

           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.

Authors: Yago Jesus, Patrick Gouin & David Reguera Garcia aka Dreg

• WARNING: if unhide process crash you can have a rootkit in the system with some bugs

Release of unhide-NG:

unhide_20200120

https://github.com/YJesus/Unhide-NG/releases

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

Detecting hidden processes. Implements some 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 ocupation (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.

7- Low level stuff, ex: assembly direct calls vs API calls. ONLY for unhide-linux version

  --altsysinfo           use alternate sysinfo test in meta-test

-l, --logfile log result into unhide-linux.log file --morecheck more checks (available only with procfs, checkopendir & checkchdir commands -v, --verbose verbose --brute bruteforce the all process IDs --brutedoublecheck bruteforce the all process IDs with double check --low assembly direct calls vs API calls, this option only works in dynamic form, use unhide-linux-dyn --proc compare /proc with the output of /bin/ps. --procall combinates --proc and --procfs --procfs compare information gathered from /bin/ps with information gathered by walking in the procfs. With --morecheck option, this test makes more checks --quick combines the --proc, --procfs and --sys in a quick way. It's about 20 times faster but may give more false positives --reverse Verify that all threads seen by ps are also seen in procfs and by system calls --sys compare information gathered from /bin/ps with information gathered from system calls -?, --help Give this help list --usage Give a short usage message -V, --version Print program version

// 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.

  -f, --show-fuser show fuser output for hidden ports -l, --logfile log result into unhide-tcp.log file -n, --use-netstat use netstat instead of ss -o, --show-lsof show lsof output for hidden ports -s, --use-quickver use very quick version for server with lot of opened ports -v, --verbose verbose -?, --help Give this help list --usage Give a short usage message -V, --version Print program version

// Unhide-gids // -----------

A lot of rootkits uses a MAGIC GID (a random GID generated) to hide processes and files. This tool find rootkits bruteforcing all GIDs possible in the system.

unhide-gids should be your last option. it can take many hours/days. but this is the only one that does not need a hidden process running to detect a rootkit.

Processes: Full GIDs process occupation (processes GID bruteforcing)

Files: Full GIDs file occupation (files GID bruteforcing)

It also can detect some rootkits safe-guards and strange things in the hooked code.

  --files-gids-readdir   bruteforce files GIDs via readdir, very slow
  --files-gids-stat      bruteforce files GIDs via stat

-l, --logfile log result into unhide-gids.log file --max-gid[=COUNT] max GID --min-gid[=COUNT] min GID --processes-gids-jail bruteforce processes GIDs and detected setgid jail

  --processes-gids-readdir   bruteforce processes GIDs via readdir, very
                         slow
  --processes-gids-stat  bruteforce processes GIDs via stat

-v, --verbose verbose -?, --help Give this help list --usage Give a short usage message -V, --version Print program version

Its possible combine args of same type ex: ./unhide-gids --processes-gids-jail --processes-gids-stat

// 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" :

• it makes three tests less (kill, opendir and chdir),
• it only run /bin/ps once at start and once for the double check,
• also, its tests are less accurate (e.g.. testing return value instead of errno),
• 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. It is very quick, about 80 times quicker than "unhide-linux quick reverse"

// Files // -----

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

unhide-gids.c -- GIDs bruteforce

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

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

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

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

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, unhide-gids and unhide-tcp.

Examples:

./unhide-linux --brute --procall

./unhide_rb

./unhide-gids --files-gids-stat --files-gids-readdir

./unhide-tcp --show-fuser --show-lsof --logfile

./unhide-linux-dyn --low

(--low option only works in dynamic form, use unhide-linux-dyn, for others options use static form)

// Anti-unhide prevention // ----------------------- Some rootkits detects unhide checking its name. Just copy the original executable with a random name, example:

cp unhide $RANDOM

cp unhide-gids $RANDOM

cp unhide-linux-dyn $RANDOM

ls

    13313  19251  19384  unhide  unhide-gids  unhide-linux-dyn

// 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