Linux Reverse Shell via Suspicious Utility

[rule]
description = """
Detects the creation of a reverse shell through a suspicious process chain spawned via a utility with suspicious command
line arguments. Reverse shells spawned by the specified utilities that are initialized from a single process followed by
a network connection attempt will be captured through this rule. Attackers may spawn reverse shells to establish
persistence onto a target system.
"""
id = "c71b9783-ca42-4532-8eb3-e8f2fe32ff39"
license = "Elastic License v2"
name = "Linux Reverse Shell via Suspicious Utility"
os_list = ["linux"]
reference = ["https://www.elastic.co/security-labs/primer-on-persistence-mechanisms"]
version = "1.0.9"

query = '''
sequence by process.entity_id with maxspan=5s
  [process where event.type == "start" and event.action  == "exec" and (
    (process.name like "python*" and process.args == "-c" and process.command_line like~ (
     "*import*pty*spawn*", "*import*subprocess*call*"
    )) or
    (process.name like "perl*" and process.args == "-e" and process.command_line like~ "*socket*" and process.command_line like~ (
     "*exec*", "*system*"
    )) or
    (process.name like "ruby*" and process.args in ("-e", "-rsocket") and process.command_line like~ (
     "*TCPSocket.new*", "*TCPSocket.open*"
     )) or
    (process.name like "lua*" and process.args == "-e" and process.command_line like~ "*socket.tcp*" and process.command_line like~ (
     "*io.popen*", "*os.execute*"
    )) or
    (process.name like "php*" and process.args == "-r" and process.command_line like~ "*fsockopen*" and process.command_line like~ "*/bin/*sh*") or 
    (process.name == "node" and process.args == "-e" and process.command_line like~ "*spawn*sh*" and process.command_line like~ "*connect*") or
    (process.name in ("awk", "gawk", "mawk", "nawk") and process.command_line like~ "*/inet/tcp/*")
   )]
  [network where event.type == "start" and event.action == "connection_attempted" and 
   process.name like ("python*", "php*", "perl", "ruby", "lua*", "*awk", "node") and not (
     destination.ip == null or destination.ip == "0.0.0.0" or cidrmatch(
       destination.ip, "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24", "192.0.0.0/29",
       "192.0.0.8/32", "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32", "192.0.0.171/32", "192.0.2.0/24",
       "192.31.196.0/24", "192.52.193.0/24", "192.168.0.0/16", "192.88.99.0/24", "224.0.0.0/4", "100.64.0.0/10",
       "192.175.48.0/24","198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4", "::1", "FE80::/10",
       "FF00::/8"
       )
    )]
'''

min_endpoint_version = "8.5.0"
optional_actions = []
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 0

[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 1

[[actions]]
action = "kill_process"
field = "process.parent.entity_id"
state = 0

[[actions]]
action = "kill_process"
field = "process.parent.entity_id"
state = 1

[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1059"
name = "Command and Scripting Interpreter"
reference = "https://attack.mitre.org/techniques/T1059/"
[[threat.technique.subtechnique]]
id = "T1059.004"
name = "Unix Shell"
reference = "https://attack.mitre.org/techniques/T1059/004/"



[threat.tactic]
id = "TA0002"
name = "Execution"
reference = "https://attack.mitre.org/tactics/TA0002/"
[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1071"
name = "Application Layer Protocol"
reference = "https://attack.mitre.org/techniques/T1071/"


[threat.tactic]
id = "TA0011"
name = "Command and Control"
reference = "https://attack.mitre.org/tactics/TA0011/"

[internal]
min_endpoint_version = "8.5.0"