Detection: Verclsid CLSID Execution

Updated Date: 2024-05-21 ID: 61e9a56a-20fa-11ec-8ba3-acde48001122 Author: Teoderick Contreras, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic detects the potential abuse of the verclsid.exe utility to execute malicious files via generated CLSIDs. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line patterns associated with verclsid.exe. This activity is significant because verclsid.exe is a legitimate Windows application used to verify CLSID COM objects, and its misuse can indicate an attempt to bypass security controls. If confirmed malicious, this technique could allow an attacker to execute arbitrary code, potentially leading to system compromise or further malicious activities.

Search

1
2| tstats `security_content_summariesonly` values(Processes.process) as process values(Processes.parent_process) as parent_process values(Processes.process_id) as process_id count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_verclsid` AND Processes.process="*/S*" Processes.process="*/C*" AND  Processes.process="*{*" AND Processes.process="*}*" by  Processes.process_name Processes.original_file_name Processes.dest Processes.user Processes.parent_process_name Processes.parent_process 
3| `drop_dm_object_name(Processes)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `verclsid_clsid_execution_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
CrowdStrike ProcessRollup2	N/A	`'crowdstrike:events:sensor'`	`'crowdstrike'`	N/A

Macros Used

Name	Value
process_verclsid	`(Processes.process_name=verclsid.exe OR Processes.original_file_name=verclsid.exe)`
verclsid_clsid_execution_filter	`search *`

verclsid_clsid_execution_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
T1218.012	Verclsid	Defense Evasion
T1218	System Binary Proxy Execution	Defense Evasion

KillChainPhase.EXPLOITAITON

NistCategory.DE_AE

Cis18Value.CIS_10

Lazarus Group

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

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

windows can used this application for its normal COM object validation.

Associated Analytic Story

Unusual Processes

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
process $process_name$ to execute possible clsid commandline $process$ in $dest$	25	50	50

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

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: 2