Suspicious Windows Defender Registry Key Tampering Via Reg.EXE

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About the rule

Rule Type

Standard

Rule Description

Detects the usage of "reg.exe" to tamper with different Windows Defender registry keys in order to disable some important features related to protection and detection

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Process started" AND ((PROCESSNAME endswith "\reg.exe" OR ORIGINALFILENAME = "reg.exe") AND COMMANDLINE contains "SOFTWARE\Microsoft\Windows Defender\,SOFTWARE\Policies\Microsoft\Windows Defender Security Center,SOFTWARE\Policies\Microsoft\Windows Defender") AND (((COMMANDLINE contains " add " AND COMMANDLINE contains "d 0") AND COMMANDLINE contains "DisallowExploitProtectionOverride,EnableControlledFolderAccess,MpEnablePus,PUAProtection,SpynetReporting,SubmitSamplesConsent,TamperProtection") OR ((COMMANDLINE contains " add " AND COMMANDLINE contains "d 1") AND COMMANDLINE contains "DisableAccess,DisableAntiSpyware,DisableAntiSpywareRealtimeProtection,DisableAntiVirus,DisableAntiVirusSignatures,DisableArchiveScanning,DisableBehaviorMonitoring,DisableBlockAtFirstSeen,DisableCloudProtection,DisableConfig,DisableEnhancedNotifications,DisableIntrusionPreventionSystem,DisableIOAVProtection,DisableNetworkProtection,DisableOnAccessProtection,DisablePrivacyMode,DisableRealtimeMonitoring,DisableRoutinelyTakingAction,DisableScanOnRealtimeEnable,DisableScriptScanning,DisableSecurityCenter,Notification_Suppress,SignatureDisableUpdateOnStartupWithoutEngine")) select Action1.HOSTNAME,Action1.MESSAGE,Action1.COMMANDLINE,Action1.FILE_NAME,Action1.PROCESSNAME,Action1.USERNAME,Action1.PARENTPROCESSNAME

Detection

Execution Mode

realtime

Log Sources

Windows

Author

Florian Roth (Nextron Systems), Swachchhanda Shrawan Poudel, Nasreddine Bencherchali (Nextron Systems)