Executable File Modification via SSH

[rule]
description = """
Detects executable file creation or modification via SSH sessions in temporary directories. This indicates potential
malware deployment or tool staging by threat actors.
"""
id = "47205a9a-836c-4bed-b068-575eed26478d"
license = "Elastic License v2"
name = "Executable File Modification via SSH"
os_list = ["macos"]
version = "1.0.5"

query = '''
file where event.action == "modification" and file.Ext.header_bytes like~ ("cffaedfe*", "cafebabe*") and
 file.path like ("/Users/Shared/*", "/tmp/*", "/private/tmp/*", "/var/tmp/*", "/private/var/tmp/*") and 
 (process.name in ("ssh", "sshd", "sshd-session") or Effective_process.name in ("ssh", "sshd", "sshd-session")) and
 not process.code_signature.subject_name like "Software Signing"
'''

min_endpoint_version = "8.16.0"
optional_actions = []
[[actions]]
action = "kill_process"
field = "Effective_process.entity_id"
state = 0

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

[[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 = "T1105"
name = "Ingress Tool Transfer"
reference = "https://attack.mitre.org/techniques/T1105/"


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

[internal]
min_endpoint_version = "8.16.0"