Potential Persistence Via Shim Database In Uncommon Location

Status: test
Severity: high
Log source: category registry_set, product windows
Author: Nasreddine Bencherchali (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects the installation of a new shim database where the file is located in a non-default location

MITRE ATT&CK coverage

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

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 13: RegistryEvent (Value Set)

Rule body

title: Potential Persistence Via Shim Database In Uncommon Location
id: 6b6976a3-b0e6-4723-ac24-ae38a737af41
status: test
description: Detects the installation of a new shim database where the file is located in a non-default location
references:
    - https://www.fireeye.com/blog/threat-research/2017/05/fin7-shim-databases-persistence.html
    - https://andreafortuna.org/2018/11/12/process-injection-and-persistence-using-application-shimming/
    - https://www.blackhat.com/docs/asia-14/materials/Erickson/Asia-14-Erickson-Persist-It-Using-And-Abusing-Microsofts-Fix-It-Patches.pdf
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-08-01
modified: 2023-08-17
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.011
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains|all:
            - '\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\InstalledSDB\'
            - '\DatabasePath'
    filter_main_known_locations:
        Details|contains: ':\Windows\AppPatch\Custom'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_*

Stage 1: `selection`

selection:
    TargetObject|contains|all:
        - '\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\InstalledSDB\'
        - '\DatabasePath'

Stage 2: `not filter_main_known_locations`

filter_main_known_locations:
    Details|contains: ':\Windows\AppPatch\Custom'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`Details`	match	`:\Windows\AppPatch\Custom`	`excludes:Details` `field:"Details" value:":\Windows\AppPatch\Custom"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`TargetObject`	match	`\DatabasePath` `\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\InstalledSDB\` corpus 2 (sigma 2)	`field:"TargetObject" kind:match`

Potential Persistence Via Shim Database In Uncommon Location

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection

Stage 2: not filter_main_known_locations

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter_main_known_locations`