ID | Technique | Tactic |
---|---|---|
T1220 | XSL Script Processing | Defense Evasion |
Detection: WMIC XSL Execution via URL
Description
The following analytic detects wmic.exe
loading a remote XSL script via a URL. This detection leverages Endpoint Detection and Response (EDR) data, focusing on command-line executions that include HTTP/HTTPS URLs and the /FORMAT switch. This activity is significant as it indicates a potential application control bypass, allowing adversaries to execute JScript or VBScript within an XSL file. If confirmed malicious, this technique can enable attackers to execute arbitrary code, escalate privileges, or maintain persistence using a trusted Windows tool, posing a severe threat to the environment.
Search
1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_wmic` Processes.process IN ("*http://*", "*https://*") Processes.process="*/format:*" by Processes.parent_process_name Processes.original_file_name Processes.parent_process Processes.process_name Processes.process_id Processes.process Processes.dest Processes.user
3| `drop_dm_object_name(Processes)`
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| `wmic_xsl_execution_via_url_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
CrowdStrike ProcessRollup2 | N/A | 'crowdstrike:events:sensor' |
'crowdstrike' |
N/A |
Macros Used
Name | Value |
---|---|
process_wmic | (Processes.process_name=wmic.exe OR Processes.original_file_name=wmic.exe) |
wmic_xsl_execution_via_url_filter | search * |
wmic_xsl_execution_via_url_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
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
False positives are limited as legitimate applications typically do not download files or xsl using WMIC. Filter as needed.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ utilizing wmic to download a remote XSL script. | 80 | 80 | 100 |
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: 3