Query: Sigma rule for Detects modifications or creations of Windows Defender's default threat action settings based on severity to 'allow' or
Matching passage: Sigma rule: Detects modifications or creations of Windows Defender's default threat action settings based on severity to 'allow' or. Logsource: windows / registry_event. Rule: title: Windows Defender Threat Severity Default Action Modified id: 5a9e1b2c-8f7d-4a1e-9b3c-0f6d7e5a4b1f related: - id: 1e8a9b4d-3c2a-4f9b-8d1e-7c6a5b4f3d2e type: similar status: experimental description: 'Detects modifications or creations of Windows Defender''s default threat action settings based on severity to ''allow'' or take ''no action''. This is a highly suspicious configuration change that effectively disables Defender''s ability to automatically mitigate threats of a certain severity level, allowing malicious software to run unimpeded. An attacker might use this technique to bypass defenses before executing payloads. ' references: - https://learn.microsoft.com/en-us/powershell/module/defender/set-mppreference - https://learn.microsoft.com/en-us/windows-hardware/customize/desktop/unattend/security-malware-windows-defender-threatseveritydefaultaction - https://research.splunk.com/endpoint/7215831c-8252-4ae3-8d43-db588e82f952 - https://gist.github.com/Dump-GUY/8daef859f382b895ac6fd0cf094555d2 - https://thedfirreport.com/2021/10/18/icedid-to-xinglocker-ransomware-in-24-hours/ author: Matt Anderson (Huntress) date: 2025-07-11 tags: - attack.defense-impairment - attack.t1685 logsource: category: registry_event product: windows detection: selection: TargetObject|contains: \Microsoft\Windows Defender\Threats\ThreatSeverityDefaultAction\ TargetObject|endswith: - \1 - \2 - \4 - \5 Details: - DWORD (0x00000006) - DWORD (0x00000009) condition: selection falsepositives: - Legitimate administration via scripts or tools (e.g., SCCM, Intune, GPO enforcement). Correlate with administrative activity. - Software installations that legitimately modify Defender settings (less common for these specific keys). level: high
Near-miss passage: Sigma rule: Detects the creation of a named pipe as used by CobaltStrike. Logsource: windows / pipe_created. Rule: title: CobaltStrike Named Pipe id: d5601f8c-b26f-4ab0-9035-69e11a8d4ad2 related: - id: 85adeb13-4fc9-4e68-8a4a-c7cb2c336eb7 type: similar - id: 0e7163d4-9e19-4fa7-9be6-000c61aad77a type: similar status: test description: Detects the creation of a named pipe as used by CobaltStrike references: - https://twitter.com/d4rksystem/status/1357010969264873472 - https://labs.f-secure.com/blog/detecting-cobalt-strike-default-modules-via-named-pipe-analysis/ - https://github.com/SigmaHQ/sigma/issues/253 - https://blog.cobaltstrike.com/2021/02/09/learn-pipe-fitting-for-all-of-your-offense-projects/ - https://redcanary.com/threat-detection-report/threats/cobalt-strike/ author: Florian Roth (Nextron Systems), Wojciech Lesicki date: 2021-05-25 modified: 2022-10-31 tags: - attack.privilege-escalation - attack.stealth - attack.t1055 logsource: product: windows category: pipe_created definition: Note that you have to configure logging for Named Pipe Events in Sysmon config (Event ID 17 and Event ID 18). The basic configuration is in popular sysmon configuration (https://github.com/SwiftOnSecurity/sysmon-config), but it is worth verifying. You can also use other repo, e.g. https://github.com/Neo23x0/sysmon-config, https://github.com/olafhartong/sysmon-modular. How to test detection? You can always use Cobalt Strike, but also you can check powershell script from this site https://svch0st.medium.com/guide-to-named-pipes-and-hunting-for-cobalt-strike-pipes-dc46b2c5f575 detection: selection_MSSE: PipeName|contains|all: - \MSSE- - -server selection_postex: PipeName|startswith: \postex_ selection_status: PipeName|startswith: \status_ selection_msagent: PipeName|startswith: \msagent_ selection_mojo: PipeName|startswith: \mojo_ selection_interprocess: PipeName|startswith: \interprocess_ selection_samr: PipeName|startswith: \samr_ selection_netlogon: PipeName|startswith: \netlogon_ selection_srvsvc: PipeName|startswith: \srvsvc_ selection_lsarpc: PipeName|startswith: \lsarpc_ selection_wkssvc: PipeName|startswith: \wkssvc_ condition: 1 of selection* falsepositives: - Unknown level: critical