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Description

This search looks for shim database files being written to default directories. The sdbinst.exe application is used to install shim database files (.sdb). According to Microsoft, a shim is a small library that transparently intercepts an API, changes the parameters passed, handles the operation itself, or redirects the operation elsewhere.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2020-12-08
  • Author: David Dorsey, Splunk
  • ID: 6e4c4588-ba2f-42fa-97e6-9f6f548eaa33

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1546.011 Application Shimming Privilege Escalation, Persistence
T1546 Event Triggered Execution Privilege Escalation, Persistence
Kill Chain Phase
  • Actions on Objectives
NIST
  • DE.CM
CIS20
  • CIS 8
CVE 


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| tstats `security_content_summariesonly` count values(Filesystem.action) values(Filesystem.file_hash) as file_hash values(Filesystem.file_path) as file_path  min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem where Filesystem.file_path=*Windows\\AppPatch\\Custom* by Filesystem.file_name Filesystem.dest 
| `security_content_ctime(lastTime)` 
| `security_content_ctime(firstTime)` 
|`drop_dm_object_name(Filesystem)` 
| `shim_database_file_creation_filter`

Macros

The SPL above uses the following Macros:

:information_source: shim_database_file_creation_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Supported Add-on (TA)

List of Splunk Add-on’s tested to work with the analytic.

Required fields

List of fields required to use this analytic.

  • _time
  • Filesystem.file_hash
  • Filesystem.file_path
  • Filesystem.file_name
  • Filesystem.dest

How To Implement

You must be ingesting data that records the filesystem activity from your hosts to populate the Endpoint file-system data model node. If you are using Sysmon, you will need a Splunk Universal Forwarder on each endpoint from which you want to collect data.

Known False Positives

Because legitimate shim files are created and used all the time, this event, in itself, is not suspicious. However, if there are other correlating events, it may warrant further investigation.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
56.0 70 80 A process that possibly write shim database in $file_path$ in host $dest$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 3