NAME¶
unhide — forensic tool to find hidden processes
SYNOPSIS¶
unhide [
OPTIONS]
TEST_LIST
DESCRIPTION¶
unhide is a forensic tool to find processes hidden by rootkits, Linux
kernel modules or by other techniques. It detects hidden processes using six
techniques.
OPTIONS¶
- -f
- Write a log file (unhide.log) in the current
directory.
- -h
- Display help
- -m
- Do more checks. As of 2010-11-21 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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 positives.
This technique is only available on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
The
checkgetaffinity technique consists of comparing information gathered
from /bin/ps with the result of call to the sched_getaffinity() system
function.
This technique is only available on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
The
checkgetprio technique consists of comparing information gathered
from /bin/ps with the result of call to the getpriority() system function.
This technique is only available on Linux 2.6 kernels.
The
checkRRgetinterval technique consists of comparing information
gathered from /bin/ps with the result of call to the sched_rr_get_interval()
system function.
This technique is only available on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
The
checkproc technique consists of comparing /proc with the output of
/bin/ps.
This technique is only available on Linux 2.6 kernels.
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 positives.
This technique is only available on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
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 on Linux 2.6 kernels.
Exit status:¶
- 0
- if OK,
- 1
- if a hidden or fake thread is found.
BUGS¶
Report
unhide bugs on the bug tracker on sourceforge
(
http://sourceforge.net/projects/unhide/)
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, Version 3 or any later
version published by the Free Software Foundation.
LICENSE¶
License GPLv3+: GNU GPL version 3 or later
<
http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO
WARRANTY, to the extent permitted by law.