Elevation via Common Log File System Exploitation

[rule]
description = """
Identifies unlevated attempt to create a BLF file using the Common Log File System (CLFS) API followed by spawning a
child process with System privileges. This may indicate a successful CLFS vulnerability exploitation for privilege
escalation.
"""
id = "54cff348-106e-42bf-bf94-ce8e3ed68440"
license = "Elastic License v2"
name = "Elevation via Common Log File System Exploitation"
os_list = ["windows"]
reference = ["https://securelist.com/windows-clfs-exploits-ransomware/111560/"]
version = "1.0.2"

query = '''
sequence with maxspan=2m
 [file where event.action != "deletion" and not user.id : "S-1-5-18" and user.id != null and 
  _arraysearch(process.thread.Ext.call_stack, $entry, 
               $entry.symbol_info: ("*clfsw32.dll!CreateLogFile*", "*clfsw32.dll!AddLogContainerSet*"))] by process.entity_id
 [process where event.action == "start" and user.id : "S-1-5-18"] by process.parent.entity_id
'''

min_endpoint_version = "8.7.0"
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 0

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

[[optional_actions]]
action = "rollback"
field = "process.entity_id"
state = 0

[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1068"
name = "Exploitation for Privilege Escalation"
reference = "https://attack.mitre.org/techniques/T1068/"


[threat.tactic]
id = "TA0004"
name = "Privilege Escalation"
reference = "https://attack.mitre.org/tactics/TA0004/"

[internal]
min_endpoint_version = "8.7.0"