Query: detect Detects usage of known powershell cmdlets such as "Clear-EventLog" to clear the Windows event logs in 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 specific combinations of encoding methods in PowerShell via the commandline. Logsource: windows / process_creation. Rule: title: Potential Encoded PowerShell Patterns In CommandLine id: cdf05894-89e7-4ead-b2b0-0a5f97a90f2f related: - id: 5b572dcf-254b-425c-a8c5-d9af6bea35a6 type: similar status: test description: Detects specific combinations of encoding methods in PowerShell via the commandline references: - https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=65 author: Teymur Kheirkhabarov (idea), Vasiliy Burov (rule), oscd.community, Tim Shelton date: 2020-10-11 modified: 2023-01-26 tags: - attack.stealth - attack.t1027 - attack.execution - attack.t1059.001 logsource: category: process_creation product: windows detection: selection_img: - Image|endswith: - \powershell.exe - \pwsh.exe - OriginalFileName: - PowerShell.EXE - pwsh.dll selection_to_1: CommandLine|contains: - ToInt - ToDecimal - ToByte - ToUint - ToSingle - ToSByte selection_to_2: CommandLine|contains: - ToChar - ToString - String selection_gen_1: CommandLine|contains|all: - char - join selection_gen_2: CommandLine|contains|all: - split - join condition: selection_img and (all of selection_to_* or 1 of selection_gen_*) falsepositives: - Unknown level: low