Detection: Web JSP Request via URL

Updated Date: 2024-11-15 ID: 2850c734-2d44-4431-8139-1a56f6f54c01 Author: Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies URL requests associated with CVE-2022-22965 (Spring4Shell) exploitation attempts, specifically targeting webshell access on a remote webserver. It detects HTTP GET requests with URLs containing ".jsp?cmd=" or "j&cmd=" patterns. This activity is significant as it indicates potential webshell deployment, which can lead to unauthorized remote command execution. If confirmed malicious, attackers could gain control over the webserver, execute arbitrary commands, and potentially escalate privileges, leading to severe data breaches and system compromise.

1
2| tstats count from datamodel=Web where Web.http_method IN ("GET") Web.url IN ("*.jsp?cmd=*","*j&cmd=*") by Web.http_user_agent Web.http_method, Web.url,Web.url_length Web.src, Web.dest sourcetype 
3| `drop_dm_object_name("Web")` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `web_jsp_request_via_url_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($field$)
web_jsp_request_via_url_filter search *
web_jsp_request_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

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1505.003 Web Shell Persistence
T1505 Server Software Component Persistence
T1190 Exploit Public-Facing Application Initial Access
T1133 External Remote Services Initial Access
Delivery
Installation
DE.CM
CIS 13

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

To successfully implement this search you need to be ingesting information on Web traffic that include fields relavent for traffic into the Web datamodel.

Known False Positives

False positives may be present with legitimate applications. Attempt to filter by dest IP or use Asset groups to restrict to servers.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

A suspicious URL has been requested against $dest$ by $src$, related to web shell activity.

Risk Object Risk Object Type Risk Score Threat Objects
dest system 72 src

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset /var/log/nginx/access.log nginx:plus:kv
Integration ✅ Passing Dataset /var/log/nginx/access.log 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: 4