defense_evasion_suspicious_certutil_commands.toml

[metadata]
creation_date = "2020/02/18"
maturity = "production"
updated_date = "2021/05/06"

[rule]
author = ["Elastic"]
description = """
Identifies suspicious commands being used with certutil.exe. CertUtil is a native Windows component which is part of 
Certificate Services. CertUtil is often abused by attackers to live off the land for stealthier command and control or 
data exfiltration.
"""
from = "now-9m"
index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
language = "eql"
license = "Elastic License v2"
name = "Suspicious CertUtil Commands"
references = [
    "https://twitter.com/Moriarty_Meng/status/984380793383370752",
    "https://twitter.com/egre55/status/1087685529016193025",
    "https://www.sysadmins.lv/blog-en/certutil-tips-and-tricks-working-with-x509-file-format.aspx",
    "https://docs.microsoft.com/en-us/archive/blogs/pki/basic-crl-checking-with-certutil",
]
risk_score = 47
rule_id = "fd70c98a-c410-42dc-a2e3-761c71848acf"
severity = "medium"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Defense Evasion"]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where event.type == "start" and
  (process.name : "certutil.exe" or process.pe.original_file_name == "CertUtil.exe") and 
  process.args : ("?decode", "?encode", "?urlcache", "?verifyctl", "?encodehex", "?decodehex")
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1140"
reference = "https://attack.mitre.org/techniques/T1140/"
name = "Deobfuscate/Decode Files or Information"


[rule.threat.tactic]
id = "TA0005"
reference = "https://attack.mitre.org/tactics/TA0005/"
name = "Defense Evasion"