Suspicious Shim Database Patching Activity

Severity: high
Author: Nasreddine Bencherchali (Nextron Systems)
Source: upstream

Detects installation of new shim databases that try to patch sections of known processes for potential process injection or persistence.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1546.011` Event Triggered Execution: Application Shimming
Privilege Escalation	`T1546.011` Event Triggered Execution: Application Shimming

Event coverage

Provider	Event ID	Title
Sysmon	13	RegistryEvent (Value Set)

Stages and Predicates

Stage 1: `selection`

or:
TargetObject|endswith: '\RuntimeBroker.exe'
TargetObject|endswith: '\WmiPrvSe.exe'
TargetObject|endswith: '\csrss.exe'
TargetObject|endswith: '\dllhost.exe'
TargetObject|endswith: '\explorer.exe'
TargetObject|endswith: '\services.exe'
TargetObject|endswith: '\sihost.exe'
TargetObject|endswith: '\svchost.exe'
TargetObject|endswith: '\taskhostw.exe'
TargetObject|endswith: '\winlogon.exe'
TargetObject|contains: '\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Custom\'

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.