SigmaHQ/rules/windows/builtin/win_net_ntlm_downgrade.yml

--- 
action: global
title: NetNTLM Downgrade Attack
description: Detects post exploitation using NetNTLM downgrade attacks
references: 
    - https://www.optiv.com/blog/post-exploitation-using-netntlm-downgrade-attacks
author: Florian Roth
date: 2018/03/20
tags:
    - attack.credential_access
    - attack.t1212
detection:
    condition: 1 of them
falsepositives:
    - Unknown
level: critical
--- 
logsource:
    product: windows
    service: sysmon
detection:
    selection1:
        EventID: 13
        TargetObject: 
            - '*SYSTEM\*ControlSet*\Control\Lsa\lmcompatibilitylevel'
            - '*SYSTEM\*ControlSet*\Control\Lsa\NtlmMinClientSec'
            - '*SYSTEM\*ControlSet*\Control\Lsa\RestrictSendingNTLMTraffic'
---
# Windows Security Eventlog: Process Creation with Full Command Line
logsource:
    product: windows
    service: security
    definition: 'Requirements: Audit Policy : Object Access > Audit Registry (Success)'
detection:
    selection2:
        EventID: 4657
        ObjectName: '\REGISTRY\MACHINE\SYSTEM\*ControlSet*\Control\Lsa'
        ObjectValueName: 
            - 'LmCompatibilityLevel'
            - 'NtlmMinClientSec'
            - 'RestrictSendingNTLMTraffic'