Query: detection rule: Detects usage of known powershell cmdlets such as "Clear-EventLog" to clear the Windows event logs
Matching passage: Sigma rule: Detects usage of known powershell cmdlets such as "Clear-EventLog" to clear the Windows event logs. Logsource: windows / ps_script. Rule: title: Suspicious Eventlog Clear id: 0f017df3-8f5a-414f-ad6b-24aff1128278 related: - id: cc36992a-4671-4f21-a91d-6c2b72a2edf5 type: derived status: test description: Detects usage of known powershell cmdlets such as "Clear-EventLog" to clear the Windows event logs references: - https://twitter.com/oroneequalsone/status/1568432028361830402 - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1070.001/T1070.001.md - https://eqllib.readthedocs.io/en/latest/analytics/5b223758-07d6-4100-9e11-238cfdd0fe97.html - https://stackoverflow.com/questions/66011412/how-to-clear-a-event-log-in-powershell-7 - https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.eventing.reader.eventlogsession.clearlog?view=windowsdesktop-9.0&viewFallbackFrom=dotnet-plat-ext-5.0#System_Diagnostics_Eventing_Reader_EventLogSession_ClearLog_System_String_ - https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.eventlog.clear author: Nasreddine Bencherchali (Nextron Systems), Swachchhanda Shrawan Poudel (Nextron Systems) date: 2022-09-12 modified: 2025-10-06 tags: - attack.defense-impairment - attack.t1685.005 logsource: product: windows category: ps_script definition: 'Requirements: Script Block Logging must be enabled' detection: selection: - ScriptBlockText|contains: - 'Clear-EventLog ' - 'Remove-EventLog ' - 'Limit-EventLog ' - 'Clear-WinEvent ' - ScriptBlockText|contains|all: - Eventing.Reader.EventLogSession - ClearLog - ScriptBlockText|contains|all: - Diagnostics.EventLog - Clear condition: selection falsepositives: - Rare need to clear logs before doing something. Sometimes used by installers or cleaner scripts. The script should be investigated to determine if it's legitimate level: medium
Near-miss passage: Sigma rule: Detects the modification of VPN SSL Settings (for example, the modification of authentication rules). This behavior was. Logsource: fortigate / event. Rule: title: FortiGate - VPN SSL Settings Modified id: 8b5dacf2-aeb7-459d-b133-678eb696d410 status: experimental description: 'Detects the modification of VPN SSL Settings (for example, the modification of authentication rules). This behavior was observed in pair with the addition of a VPN SSL Web Portal. ' references: - https://www.fortiguard.com/psirt/FG-IR-24-535 - https://docs.fortinet.com/document/fortigate/7.6.4/fortios-log-message-reference/398/event - https://docs.fortinet.com/document/fortigate/7.6.4/cli-reference/114404382/config-vpn-ssl-settings - https://docs.fortinet.com/document/fortigate/7.6.4/fortios-log-message-reference/44546/44546-logid-event-config-attr author: Marco Pedrinazzi (@pedrinazziM) (InTheCyber) date: 2025-11-01 tags: - attack.persistence - attack.initial-access - attack.t1133 logsource: product: fortigate service: event detection: selection: action: Edit cfgpath: vpn.ssl.settings condition: selection falsepositives: - VPN SSL settings can be changed for legitimate purposes. level: medium