Query: rule covering 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 various command line and scripting engines/processes such as "PowerShell", "Wscript", "Cmd", etc. spawning a "re. Logsource: windows / process_creation. Rule: title: Scripting/CommandLine Process Spawned Regsvr32 id: ab37a6ec-6068-432b-a64e-2c7bf95b1d22 related: - id: 8e2b24c9-4add-46a0-b4bb-0057b4e6187d type: obsolete status: test description: Detects various command line and scripting engines/processes such as "PowerShell", "Wscript", "Cmd", etc. spawning a "regsvr32" instance. references: - https://web.archive.org/web/20171001085340/https://subt0x10.blogspot.com/2017/04/bypass-application-whitelisting-script.html - https://app.any.run/tasks/34221348-072d-4b70-93f3-aa71f6ebecad/ author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems) date: 2023-05-26 tags: - attack.stealth - attack.t1218.010 logsource: category: process_creation product: windows detection: selection: ParentImage|endswith: - \cmd.exe - \cscript.exe - \mshta.exe - \powershell_ise.exe - \powershell.exe - \pwsh.exe - \wscript.exe Image|endswith: \regsvr32.exe filter_main_rpcproxy: ParentImage: C:\Windows\System32\cmd.exe CommandLine|endswith: ' /s C:\Windows\System32\RpcProxy\RpcProxy.dll' condition: selection and not 1 of filter_main_* falsepositives: - Legitimate ".bat", ".hta", ".ps1" or ".vbs" scripts leverage legitimately often. Apply additional filter and exclusions as necessary - Some legitimate Windows services level: medium