Potential Shim Database Persistence via Sdbinst.EXE

Severity: medium
Author: Markus Neis
Source: upstream

Detects installation of a new shim using sdbinst.exe. Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by application shims

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	1	Process creation

Stages and Predicates

Stage 1: `all of selection_img`

or:
Image|endswith: '\sdbinst.exe'
OriginalFileName: sdbinst.exe

Stage 2: `all of selection_cli`

CommandLine|contains: .sdb

Stage 3: `not 1 of filter_optional_iis`

or:
CommandLine|contains: ':\Program Files (x86)\IIS Express\iisexpressshim.sdb'
CommandLine|contains: ':\Program Files\IIS Express\iisexpressshim.sdb'
ParentImage|endswith: '\msiexec.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
`CommandLine`	match	`.sdb` corpus 2 (sigma 2) `:\Program Files (x86)\IIS Express\iisexpressshim.sdb` `:\Program Files\IIS Express\iisexpressshim.sdb`
`Image`	ends_with	`\sdbinst.exe` corpus 2 (sigma 2)
`OriginalFileName`	eq	`sdbinst.exe` corpus 2 (sigma 2)
`ParentImage`	ends_with	`\msiexec.exe` corpus 2 (sigma 2)