[metadata]
creation_date = "2020/08/24"
maturity = "production"
updated_date = "2020/11/03"

[rule]
author = ["Elastic"]
description = """
Identifies suspicious instances of the Windows Error Reporting process (WerFault.exe or Wermgr.exe) with matching
command-line and process executable values performing outgoing network connections. This may be indicative of a
masquerading attempt to evade suspicious child process behavior detections.
"""
false_positives = ["Legit Application Crash with rare Werfault commandline value"]
from = "now-9m"
index = ["winlogbeat-*", "logs-endpoint.events.*"]
language = "eql"
license = "Elastic License"
name = "Potential Windows Error Manager Masquerading"
references = [
    "https://twitter.com/SBousseaden/status/1235533224337641473",
    "https://www.hexacorn.com/blog/2019/09/20/werfault-command-line-switches-v0-1/",
    "https://app.any.run/tasks/26051d84-b68e-4afb-8a9a-76921a271b81/",
]
risk_score = 47
rule_id = "6ea41894-66c3-4df7-ad6b-2c5074eb3df8"
severity = "medium"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Defense Evasion"]
type = "eql"

query = '''
sequence by host.id, process.entity_id with maxspan = 5s
  [process where event.type:"start" and process.name : ("wermgr.exe", "WerFault.exe") and process.args_count == 1]
  [network where process.name : ("wermgr.exe", "WerFault.exe") and network.protocol != "dns" and
    network.direction == "outgoing" and destination.ip !="::1" and destination.ip !="127.0.0.1"
  ]
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1036"
name = "Masquerading"
reference = "https://attack.mitre.org/techniques/T1036/"


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

