Unhide is a little handy forensic tool to find hidden processes and TCP/UDP ports by rootkits / LKMs or by another hidden technique. This tools works under both Linux / Unix, and MS-Windows operating systems. From the man page:
It detects hidden processes using three techniques:
- The proc technique consists of comparing /proc with the output of /bin/ps.
- The sys technique consists of comparing information gathered from /bin/ps with information gathered from system calls.
- The brute technique consists of bruteforcing the all process IDs. This technique is only available on Linux 2.6 kernels.
Most rootkits use the power of the kernel to hide themselves, they are only visible from within the kernel. You can use unhide or tool such as rkhunter to scan for rootkits, backdoors and possible local exploits.
How do I Install Unhide?
It is recommended that you run this tool from read-only media. To install the same under Debian or Ubuntu Linux, enter:
# apt-get install unhide
Sample outputs:
Reading package lists... Done Building dependency tree Reading state information... Done Suggested packages: rkhunter The following NEW packages will be installed: unhide 0 upgraded, 1 newly installed, 0 to remove and 6 not upgraded. Need to get 822 kB of archives. After this operation, 1,872 kB of additional disk space will be used. Get:1 http://ftp.us.debian.org/debian/ squeeze/main unhide amd64 20100201-1 [822 kB] Fetched 822 kB in 5s (162 kB/s) Selecting previously deselected package unhide. (Reading database ... 166644 files and directories currently installed.) Unpacking unhide (from .../unhide_20100201-1_amd64.deb) ... Processing triggers for man-db ... Setting up unhide (20100201-1) ...
FreeBSD: Install unhide
Type the following command to install the same using the port, enter:
# cd /usr/ports/security/unhide/
# make install clean
OR, you can install the same using the binary package, enter:
# pkg_add -r unhide
unhide-tcp is a forensic tool that identifies TCP/UDP ports that are listening but are not listed in /bin/netstat through brute forcing of all TCP/UDP ports available.
How Do I Use This Tool?
You can use it as follows:
# unhide-posix proc
# unhide-posix sys
OR
# unhide-linux26 proc
# unhide-linux26 sys
# unhide-linux26 brute
Sample outputs:
Unhide 20100201
http://www.security-projects.com/?Unhide
[*]Searching for Hidden processes through kill(..,0) scanning
[*]Searching for Hidden processes through comparison of results of system calls
[*]Searching for Hidden processes through getpriority() scanning
[*]Searching for Hidden processes through getpgid() scanning
[*]Searching for Hidden processes through getsid() scanning
[*]Searching for Hidden processes through sched_getaffinity() scanning
[*]Searching for Hidden processes through sched_getparam() scanning
[*]Searching for Hidden processes through sched_getscheduler() scanning
[*]Searching for Hidden processes through sched_rr_get_interval() scanning
[*]Searching for Hidden processes through sysinfo() scanning
HIDDEN Processes Found: 1# unhide-tcp Sample outputs:
Unhide 20100201 http://www.security-projects.com/?Unhide Starting TCP checking Starting UDP checking
However, I found something interesting:
# unhide-tcp
Sample outputs:
Unhide 20100201 http://www.security-projects.com/?Unhide Starting TCP checking Found Hidden port that not appears in netstat: 1048 Found Hidden port that not appears in netstat: 1049 Found Hidden port that not appears in netstat: 1050 Starting UDP checking
The netstat -tulpn or ss commands displayed nothing about the hidden TCP ports # 1048, 1049, and 1050:
# netstat -tulpn | grep 1048
# ss -lp
# ss -l | grep 1048
See also:
- Unhide project.
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- 20 Linux System Monitoring Tools Every SysAdmin Should Know
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{ 14 comments… read them below or add one }
Above tips have been helpful….
really helpful tips, thanks a lot.
I’ll try it on my pc.
awsome tool i must say
Helpful tips. Thanks !
yum search unhide OR yum install -y unhide
then man unhide to read more…
Good article tho..
Hi,
Thanks a lot for the review, one thing,there is a bug in some kenels that gives a false positive in sysinfo() scan (as seems in your tests) please in this scenario try with the flag -r to fix it
from ./unhide-linux26 –help
-r use alternate sysinfo test in meta-test
Cheers !
So you got something running on tcp port 1048? How do I find out what is running on the port 1048?
On FreeBSD the Ports version of unhide there isn’t a “unhide-posix” command, just “unhide” and “unhide-tcp” for me once I finished compiling. Also thanks for the great recommendation!
Thanks but where is Windows ?
Really helpful tips. Thanks..
Vivek,
I found one hidden pid using [unhide brute]. Now what?
@’dincer salih kurnaz’ you can find windows version here :: http://www.unhide-forensics.info/?Windows
for P in `unhide sys | grep -v “\*” | grep -i HIDEEN | cut -f2 -d’:’ | awk ‘{print $1}’`; do kill -9 $P; done;
for P in `unhide sys | grep -v “\*” | grep -i HIDDEN | cut -f2 -d’:’ | awk ‘{print $1}’`; do kill -9 $P; done;