
title: NetNTLM Downgrade Attack
author: Florian Roth, wagga
date: 2018/03/20
description: Detects NetNTLM downgrade attack
detection:
  SELECTION_1:
    EventID: 4657
  SELECTION_2:
    ObjectName: '*\REGISTRY\MACHINE\SYSTEM*'
  SELECTION_3:
    ObjectName: '*ControlSet*'
  SELECTION_4:
    ObjectName: '*\Control\Lsa*'
  SELECTION_5:
    ObjectValueName:
    - LmCompatibilityLevel
    - NtlmMinClientSec
    - RestrictSendingNTLMTraffic
  condition: (SELECTION_1 and SELECTION_2 and SELECTION_3 and SELECTION_4 and SELECTION_5)
falsepositives:
- Unknown
id: d3abac66-f11c-4ed0-8acb-50cc29c97eed
level: critical
logsource:
  definition: 'Requirements: Audit Policy : Object Access > Audit Registry (Success)'
  product: windows
  service: security
modified: 2021/06/27
references:
- https://www.optiv.com/blog/post-exploitation-using-netntlm-downgrade-attacks
related:
- id: d67572a0-e2ec-45d6-b8db-c100d14b8ef2
  type: derived
status: experimental
tags:
- attack.defense_evasion
- attack.t1089
- attack.t1562.001
- attack.t1112
ruletype: SIGMA
