defense_evasion_posh_defender_tampering.toml

[metadata]
bypass_bbr_timing = true
creation_date = "2024/09/11"
integration = ["windows"]
maturity = "production"
updated_date = "2024/10/28"
min_stack_version = "8.14.0"
min_stack_comments = "Breaking change at 8.14.0 for the Windows Integration."


[rule]
author = ["Elastic"]
description = """
Identifies PowerShell scripts containing cmdlets and parameters that attackers can abuse to disable Windows Defender
features. Attackers can tamper with antivirus to reduce the risk of detection when executing their payloads.
"""
from = "now-9m"
index = ["winlogbeat-*", "logs-windows.powershell*"]
language = "kuery"
license = "Elastic License v2"
name = "PowerShell Script with Windows Defender Tampering Capabilities"
risk_score = 21
rule_id = "c124dc1b-cef2-4d01-8d74-ff6b0d5096b6"
setup = """## Setup

The 'PowerShell Script Block Logging' logging policy must be enabled.
Steps to implement the logging policy with Advanced Audit Configuration:

```
Computer Configuration >
Administrative Templates >
Windows PowerShell >
Turn on PowerShell Script Block Logging (Enable)
```

Steps to implement the logging policy via registry:

```
reg add "hklm\\SOFTWARE\\Policies\\Microsoft\\Windows\\PowerShell\\ScriptBlockLogging" /v EnableScriptBlockLogging /t REG_DWORD /d 1
```
"""
severity = "low"
tags = ["Domain: Endpoint", "OS: Windows", "Use Case: Threat Detection", "Tactic: Defense Evasion", "Data Source: PowerShell Logs", "Rule Type: BBR"]
timestamp_override = "event.ingested"
type = "query"
building_block_type = "default"

query = '''
event.category: "process" and host.os.type:windows and
(
  powershell.file.script_block_text: "Set-MpPreference" and
  powershell.file.script_block_text: (
    DisableArchiveScanning or DisableBehaviorMonitoring or
    DisableIntrusionPreventionSystem or DisableIOAVProtection or
    DisableRemovableDriveScanning or DisableBlockAtFirstSeen or
    DisableScanningMappedNetworkDrivesForFullScan or
    DisableScanningNetworkFiles or DisableScriptScanning or
    DisableRealtimeMonitoring or LowThreatDefaultAction or
    ModerateThreatDefaultAction or HighThreatDefaultAction
  )
)
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1562"
name = "Impair Defenses"
reference = "https://attack.mitre.org/techniques/T1562/"
[[rule.threat.technique.subtechnique]]
id = "T1562.001"
name = "Disable or Modify Tools"
reference = "https://attack.mitre.org/techniques/T1562/001/"



[rule.threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"
[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1059"
name = "Command and Scripting Interpreter"
reference = "https://attack.mitre.org/techniques/T1059/"
[[rule.threat.technique.subtechnique]]
id = "T1059.001"
name = "PowerShell"
reference = "https://attack.mitre.org/techniques/T1059/001/"



[rule.threat.tactic]
id = "TA0002"
name = "Execution"
reference = "https://attack.mitre.org/tactics/TA0002/"