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 |
Detection: Spring4Shell Payload URL Request
Description
The following analytic detects attempts to exploit the Spring4Shell vulnerability (CVE-2022-22963) by identifying specific URL patterns associated with web shell payloads. It leverages web traffic data, focusing on HTTP GET requests with URLs containing indicators like "tomcatwar.jsp," "poc.jsp," and "shell.jsp." This activity is significant as it suggests an attacker is trying to deploy a web shell, which can lead to remote code execution. If confirmed malicious, this could allow the attacker to gain persistent access, execute arbitrary commands, and potentially escalate privileges within the compromised environment.
Search
1
2| tstats count from datamodel=Web where Web.http_method IN ("GET") Web.url IN ("*tomcatwar.jsp*","*poc.jsp*","*shell.jsp*") 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| `spring4shell_payload_url_request_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($field$) |
spring4shell_payload_url_request_filter | search * |
spring4shell_payload_url_request_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
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
The jsp file names are static names used in current proof of concept code. =
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
A URL was requested related to Spring4Shell POC code on $dest$ by $src$. | 36 | 60 | 60 |
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: 3