[rule]
description = """
Identifies unlevated attempt to create a BLF file using the Common Log File System (CLFS) API followed by any activity
where the effective user.id is System. This may indicate a successful CLFS vulnerability exploitation for privilege
escalation.
"""
id = "cac42a72-dc66-45a4-9809-109f5f33c16e"
license = "Elastic License v2"
name = "Potential Common Log File System Vulnerability Exploitation"
os_list = ["windows"]
reference = ["https://securelist.com/windows-clfs-exploits-ransomware/111560/"]
version = "1.0.2"
query = '''
sequence by process.entity_id 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*"))]
[any where event.category : ("file", "registry", "api") and user.id : "S-1-5-18"]
'''
min_endpoint_version = "8.7.0"
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 0
[[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"