Change Winevt Channel Access Permission Via Registry

Severity: high
Author: frack113
Source: upstream

Detects tampering with the "ChannelAccess" registry key in order to change access to Windows event channel.

MITRE ATT&CK coverage

Tactic	Techniques
Defense Evasion	`T1562.002` Impair Defenses: Disable Windows Event Logging

Event coverage

Provider	Event ID	Title
Sysmon	13	RegistryEvent (Value Set)

Stages and Predicates

Stage 1: `selection`

or:
Details|contains: '(A;;0x1;;;LA)'
Details|contains: '(A;;0x1;;;SY)'
Details|contains: '(A;;0x5;;;BA)'
TargetObject|endswith: '\ChannelAccess'
TargetObject|contains: '\Microsoft\Windows\CurrentVersion\WINEVT\Channels\'

Stage 2: `not 1 of filter_main_*`

or:
Image|endswith: '\TiWorker.exe'
Image|startswith: 'C:\Windows\WinSxS\'
Image: 'C:\Windows\servicing\TrustedInstaller.exe'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`Details`	match	`(A;;0x1;;;LA)` `(A;;0x1;;;SY)` `(A;;0x5;;;BA)`
`Image`	ends_with	`\TiWorker.exe` corpus 7 (sigma 7)
`Image`	eq	`C:\Windows\servicing\TrustedInstaller.exe` corpus 3 (sigma 3)
`Image`	starts_with	`C:\Windows\WinSxS\` corpus 13 (sigma 13)
`TargetObject`	ends_with	`\ChannelAccess` corpus 2 (sigma 2)
`TargetObject`	match	`\Microsoft\Windows\CurrentVersion\WINEVT\Channels\` corpus 2 (sigma 2)