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Description

The following analytic identifies the process java writing a .jsp to disk. This is potentially indicative of a web shell being written to disk.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2022-04-05
  • Author: Michael Haag, Splunk
  • ID: eb65619c-4f8d-4383-a975-d352765d344b

Annotations

ATT&CK
ID Technique Tactic
T1190 Exploit Public-Facing Application Initial Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
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 `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where Processes.process_name IN ("java","java.exe", "javaw.exe") by _time Processes.process_id Processes.process_name Processes.dest Processes.process_guid Processes.user 
| `drop_dm_object_name(Processes)` 
| join process_guid [
| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Filesystem where Filesystem.file_name="*.jsp*" by _time Filesystem.dest Filesystem.file_create_time Filesystem.file_name Filesystem.file_path Filesystem.process_guid Filesystem.user 
| `drop_dm_object_name(Filesystem)` 
| fields _time process_guid file_path file_name file_create_time user dest process_name] 
| stats count min(_time) as firstTime max(_time) as lastTime by dest process_name process_guid file_name file_path file_create_time user 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `java_writing_jsp_file_filter`

Macros

The SPL above uses the following Macros:

Note that java_writing_jsp_file_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

  • _time
  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.original_file_name
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_path
  • Processes.process_path
  • Processes.parent_process_id
  • Filesystem.dest
  • Filesystem.file_create_time
  • Filesystem.file_name
  • Filesystem.file_path
  • Filesystem.process_guid
  • Filesystem.user

How To Implement

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes and Filesystem node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Known False Positives

False positives are possible and filtering may be required. Restrict by assets or filter known jsp files that are common for the environment.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
42.0 60 70 An instance of $process_name$ was identified on endpoint $dest$ writing a jsp file to disk, potentially indicative of exploitation.

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

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