UAC Bypass via DiskCleanup Scheduled Task Hijack

  1[metadata]
  2creation_date = "2020/08/18"
  3integration = ["endpoint", "windows", "system"]
  4maturity = "production"
  5updated_date = "2024/05/21"
  6
  7[rule]
  8author = ["Elastic"]
  9description = """
 10Identifies User Account Control (UAC) bypass via hijacking DiskCleanup Scheduled Task. Attackers bypass UAC to
 11stealthily execute code with elevated permissions.
 12"""
 13from = "now-9m"
 14index = [
 15    "winlogbeat-*",
 16    "logs-endpoint.events.process-*",
 17    "logs-windows.*",
 18    "endgame-*",
 19    "logs-system.security*",
 20]
 21language = "eql"
 22license = "Elastic License v2"
 23name = "UAC Bypass via DiskCleanup Scheduled Task Hijack"
 24risk_score = 47
 25rule_id = "1dcc51f6-ba26-49e7-9ef4-2655abb2361e"
 26setup = """## Setup
 27
 28If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2,
 29events will not define `event.ingested` and default fallback for EQL rules was not added until version 8.2.
 30Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
 31`event.ingested` to @timestamp.
 32For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
 33"""
 34severity = "medium"
 35tags = [
 36    "Domain: Endpoint",
 37    "OS: Windows",
 38    "Use Case: Threat Detection",
 39    "Tactic: Privilege Escalation",
 40    "Tactic: Defense Evasion",
 41    "Tactic: Execution",
 42    "Data Source: Elastic Endgame",
 43    "Data Source: Elastic Defend",
 44]
 45timestamp_override = "event.ingested"
 46type = "eql"
 47
 48query = '''
 49process where host.os.type == "windows" and event.type == "start" and
 50 process.args : "/autoclean" and process.args : "/d" and process.executable != null and 
 51 not process.executable : ("C:\\Windows\\System32\\cleanmgr.exe",
 52                           "C:\\Windows\\SysWOW64\\cleanmgr.exe",
 53                           "C:\\Windows\\System32\\taskhostw.exe")
 54'''
 55
 56
 57[[rule.threat]]
 58framework = "MITRE ATT&CK"
 59[[rule.threat.technique]]
 60id = "T1548"
 61name = "Abuse Elevation Control Mechanism"
 62reference = "https://attack.mitre.org/techniques/T1548/"
 63[[rule.threat.technique.subtechnique]]
 64id = "T1548.002"
 65name = "Bypass User Account Control"
 66reference = "https://attack.mitre.org/techniques/T1548/002/"
 67
 68
 69
 70[rule.threat.tactic]
 71id = "TA0004"
 72name = "Privilege Escalation"
 73reference = "https://attack.mitre.org/tactics/TA0004/"
 74[[rule.threat]]
 75framework = "MITRE ATT&CK"
 76[[rule.threat.technique]]
 77id = "T1548"
 78name = "Abuse Elevation Control Mechanism"
 79reference = "https://attack.mitre.org/techniques/T1548/"
 80[[rule.threat.technique.subtechnique]]
 81id = "T1548.002"
 82name = "Bypass User Account Control"
 83reference = "https://attack.mitre.org/techniques/T1548/002/"
 84
 85
 86
 87[rule.threat.tactic]
 88id = "TA0005"
 89name = "Defense Evasion"
 90reference = "https://attack.mitre.org/tactics/TA0005/"
 91[[rule.threat]]
 92framework = "MITRE ATT&CK"
 93[[rule.threat.technique]]
 94id = "T1053"
 95name = "Scheduled Task/Job"
 96reference = "https://attack.mitre.org/techniques/T1053/"
 97[[rule.threat.technique.subtechnique]]
 98id = "T1053.005"
 99name = "Scheduled Task"
100reference = "https://attack.mitre.org/techniques/T1053/005/"
101
102
103
104[rule.threat.tactic]
105id = "TA0002"
106name = "Execution"
107reference = "https://attack.mitre.org/tactics/TA0002/"