LSMS/scripts/search_non_kthreads.py
2021-12-27 13:52:26 +01:00

136 lines
4.5 KiB
Python
Executable file

#!/usr/bin/env python3
# written by sqall
# twitter: https://twitter.com/sqall01
# blog: https://h4des.org
# github: https://github.com/sqall01
#
# # Licensed under the MIT License.
"""
Short summary:
Malware will name itself with [brackets] to impersonate a Linux kernel thread.
Any Linux process that looks like a [kernel thread] should have an empty maps file.
Site note:
when using ps auxwf | grep "\[" they are children of [kthreadd]
Requirements:
None
Reference:
https://twitter.com/CraigHRowland/status/1232399132632813568
https://www.sandflysecurity.com/blog/detecting-linux-kernel-process-masquerading-with-command-line-forensics/
"""
import os
import socket
# Read configuration and library functions.
try:
from config.config import ALERTR_FIFO, FROM_ADDR, TO_ADDR
from config.search_non_kthreads import NON_KTHREAD_WHITELIST, ACTIVATED
from lib.alerts import raise_alert_alertr, raise_alert_mail
except:
ALERTR_FIFO = None
FROM_ADDR = None
TO_ADDR = None
NON_KTHREAD_WHITELIST = []
ACTIVATED = True
def search_suspicious_process():
# Decide where to output results.
print_output = False
if ALERTR_FIFO is None and FROM_ADDR is None and TO_ADDR is None:
print_output = True
if not ACTIVATED:
if print_output:
print("Module deactivated.")
return
# Iterate over all processes that have a "[".
fd = os.popen("ps auxw | grep \\\\[ | awk '{print $2}'")
pids_raw = fd.read().strip()
fd.close()
for pid in pids_raw.split("\n"):
# Get process name of pid.
fd = os.popen("ps u -p %s" % pid)
ps_output = fd.read().strip()
fd.close()
fd = os.popen("ps u -p %s | awk '{$1=$2=$3=$4=$5=$6=$7=$8=$9=$10=\"\"; print $0}'" % pid)
process_name_raw = fd.read().strip()
fd.close()
for process_name in process_name_raw.split("\n"):
process_name = process_name.strip()
# Ignore COMMAND since it is part of the headline of ps output.
if process_name == "COMMAND":
continue
# Check if we have whitelisted the process
# (e.g., [lxc monitor] /var/lib/lxc satellite).
elif process_name in NON_KTHREAD_WHITELIST:
continue
# Only consider process names that start with a "["
# (e.g., "avahi-daemon: running [towelie.local]"" does not)
elif process_name.startswith("["):
if print_output:
print("Checking pid: %s (%s) - " % (pid, process_name),
end="")
file_path = "/proc/%s/maps" % pid
try:
with open(file_path, 'rt') as fp:
data = fp.read()
if data == "":
if print_output:
print("ok")
continue
except Exception as e:
print("Exception")
print(e)
print("")
continue
if print_output:
print("SUSPICIOUS")
print(ps_output)
print("")
else:
if ALERTR_FIFO is not None:
hostname = socket.gethostname()
optional_data = dict()
optional_data["pid"] = pid
optional_data["ps_output"] = ps_output
optional_data["hostname"] = hostname
message = "Process with pid '%s' on host '%s' suspicious.\n\n" % (pid, hostname)
message += ps_output
optional_data["message"] = message
raise_alert_alertr(ALERTR_FIFO,
optional_data)
if FROM_ADDR is not None and TO_ADDR is not None:
hostname = socket.gethostname()
subject = "[Security] Suspicious process found on '%s'" % hostname
message = "Process with pid '%s' on host '%s' suspicious.\n\n" % (pid, hostname)
message += ps_output
raise_alert_mail(FROM_ADDR,
TO_ADDR,
subject,
message)
if __name__ == '__main__':
search_suspicious_process()