Trust Access Disable For VBApplications

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About the rule

Rule Type

Standard

Rule Description

Detects registry changes to Microsoft Office "AccessVBOM" to a value of "1" which disables trust access for VBA on the victim machine and lets attackers execute malicious macros without any Microsoft Office warnings.

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Registry value modified" AND (OBJECTNAME endswith "\Security\AccessVBOM" OR (OBJECTNAME endswith "\Security" AND OBJECTVALUENAME = "AccessVBOM")) AND (INFORMATION = "DWORD (0x00000001)" OR (CHANGES = 1 AND NEWTYPE = "REG_DWORD")) select Action1.HOSTNAME,Action1.MESSAGE,Action1.OBJECTNAME,Action1.PROCESSNAME,Action1.PREVVAL,Action1.CHANGES

Detection

Execution Mode

realtime

Log Sources

Windows

Author

Trent Liffick (@tliffick), Nasreddine Bencherchali (Nextron Systems)