Detection: WordPress Bricks Builder plugin RCE

Updated Date: 2024-09-30 ID: 56a8771a-3fda-4959-b81d-2f266e2f679f Author: Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies potential exploitation of the WordPress Bricks Builder plugin RCE vulnerability. It detects HTTP POST requests to the URL path "/wp-json/bricks/v1/render_element" with a status code of 200, leveraging the Web datamodel. This activity is significant as it indicates an attempt to exploit CVE-2024-25600, a known vulnerability that allows remote code execution. If confirmed malicious, an attacker could execute arbitrary commands on the target server, leading to potential full system compromise and unauthorized access to sensitive data.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Web where Web.url IN ("*/wp-json/bricks/v1/render_element") Web.status=200 Web.http_method=POST by Web.src, Web.dest, Web.http_user_agent, Web.url, Web.uri_path, Web.status, Web.http_method, sourcetype, source 
3| `drop_dm_object_name("Web")` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `wordpress_bricks_builder_plugin_rce_filter`

Data Source

Name Platform Sourcetype Source
Nginx Access N/A 'nginx:plus:kv' '/var/log/nginx/access.log'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
wordpress_bricks_builder_plugin_rce_filter search *
wordpress_bricks_builder_plugin_rce_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
T1190 Exploit Public-Facing Application Initial Access
KillChainPhase.DELIVERY
NistCategory.DE_CM
Cis18Value.CIS_13
APT28
APT29
APT39
APT41
APT5
Agrius
Axiom
BackdoorDiplomacy
BlackTech
Blue Mockingbird
Cinnamon Tempest
Dragonfly
Earth Lusca
Ember Bear
FIN13
FIN7
Fox Kitten
GALLIUM
GOLD SOUTHFIELD
HAFNIUM
INC Ransom
Ke3chang
Kimsuky
Magic Hound
Moses Staff
MuddyWater
Play
Rocke
Sandworm Team
Threat Group-3390
ToddyCat
Volatile Cedar
Volt Typhoon
Winter Vivern
menuPass

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
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

The search is based on data in the Web datamodel and was modeled from NGINX logs. Ensure that the Web datamodel is accelerated and that the data source for the Web datamodel is properly configured. If using other web sources, modify they query, or review the data, as needed.

Known False Positives

False positives may be possible, however we restricted it to HTTP Status 200 and POST requests, based on the POC. Upon investigation review the POST body for the actual payload - or command - being executed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Potential exploitation of the WordPress Bricks Builder plugin RCE vulnerability on $dest$ by $src$. 100 100 100
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 nginx:plus:kv nginx:plus:kv
Integration ✅ Passing Dataset nginx:plus:kv nginx:plus:kv

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