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Description

The following analytic is static indicators related to CVE-2022-22963, Spring4Shell. The 3 indicators provide an amount of fidelity that source IP is attemping to exploit a web shell on the destination. The filename and cmd are arbitrary in this exploitation. Java will write a JSP to disk and a process will spawn from Java based on the cmd passed. This is indicative of typical web shell activity.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Web
  • Last Updated: 2022-07-12
  • Author: Michael Haag, Splunk
  • ID: 9d44d649-7d67-4559-95c1-8022ff49420b

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1505.003 Web Shell Persistence
T1505 Server Software Component Persistence
T1190 Exploit Public-Facing Application Initial Access
T1133 External Remote Services Persistence, Initial Access
Kill Chain Phase
  • Installation
  • Delivery
NIST
  • DE.CM
CIS20
  • CIS 13
CVE
ID Summary CVSS
CVE-2022-22965 A Spring MVC or Spring WebFlux application running on JDK 9+ may be vulnerable to remote code execution (RCE) via data binding. The specific exploit requires the application to run on Tomcat as a WAR deployment. If the application is deployed as a Spring Boot executable jar, i.e. the default, it is not vulnerable to the exploit. However, the nature of the vulnerability is more general, and there may be other ways to exploit it. 7.5 


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| 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 
| `drop_dm_object_name("Web")` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `spring4shell_payload_url_request_filter`

Macros

The SPL above uses the following Macros:

:information_source: spring4shell_payload_url_request_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • Web.http_method
  • Web.url
  • Web.url_length
  • Web.src
  • Web.dest
  • Web.http_user_agent

How To Implement

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

RBA

Risk Score Impact Confidence Message
36.0 60 60 A URL was requested related to Spring4Shell POC code on $dest$ by $src$.

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

Reference

Test Dataset

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 | version: 1