Query: alert when 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: Remove SD (Security Descriptor) value in \Schedule\TaskCache\Tree registry hive to hide schedule task. This technique is. Logsource: windows / registry_delete. Rule: title: Removal Of SD Value to Hide Schedule Task - Registry id: acd74772-5f88-45c7-956b-6a7b36c294d2 related: - id: 526cc8bc-1cdc-48ad-8b26-f19bff969cec type: similar status: test description: Remove SD (Security Descriptor) value in \Schedule\TaskCache\Tree registry hive to hide schedule task. This technique is used by Tarrask malware references: - https://www.microsoft.com/security/blog/2022/04/12/tarrask-malware-uses-scheduled-tasks-for-defense-evasion/ author: Sittikorn S date: 2022-04-15 modified: 2025-10-25 tags: - attack.defense-impairment - attack.t1685 logsource: product: windows category: registry_delete detection: selection: TargetObject|contains|all: - \SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\TaskCache\Tree\ - SD condition: selection falsepositives: - Unknown level: medium regression_tests_path: regression_data/rules/windows/registry/registry_delete/registry_delete_schtasks_hide_task_via_sd_value_removal/info.yml