Detection: Windows New InProcServer32 Added

Updated Date: 2024-11-13 ID: 0fa86e31-0f73-4ec7-9ca3-dc88e117f1db Author: Michael Haag, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic detects the addition of new InProcServer32 registry keys on Windows endpoints. It leverages data from the Endpoint.Registry datamodel to identify changes in registry paths associated with InProcServer32. This activity is significant because malware often uses this mechanism to achieve persistence or execute malicious code by registering a new InProcServer32 key pointing to a harmful DLL. If confirmed malicious, this could allow an attacker to persist in the environment or execute arbitrary code, posing a significant threat to system integrity and security.

1
2| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry where Registry.registry_path="*\\InProcServer32\\*" by Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.dest Registry.process_guid Registry.user 
3| `drop_dm_object_name(Registry)` 
4|`security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_new_inprocserver32_added_filter`

Data Source

Name Platform Sourcetype Source
Sysmon EventID 13 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
windows_new_inprocserver32_added_filter search *
windows_new_inprocserver32_added_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1112 Modify Registry Defense Evasion
Exploitation
DE.AE
CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Risk Event False
This configuration file applies to all detections of type hunting.

Implementation

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Registry node.

Known False Positives

False positives are expected. Filtering will be needed to properly reduce legitimate applications from the results.

Associated Analytic Story

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational XmlWinEventLog
Integration ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational XmlWinEventLog

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: GitHub | Version: 5