web_jsp_request_via_url.yml

name: Web JSP Request via URL
id: 2850c734-2d44-4431-8139-1a56f6f54c01
version: 1
date: '2022-04-05'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies the common URL requests used by a recent
  CVE - CVE-2022-22965, or Spring4Shell, to access a webshell on the remote webserver.
  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.
data_source: 
- Nginx Access
search: '| 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 | `drop_dm_object_name("Web")` | `security_content_ctime(firstTime)`
  | `security_content_ctime(lastTime)` | `web_jsp_request_via_url_filter`'
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: False positives may be present with legitimate applications.
  Attempt to filter by dest IP or use Asset groups to restrict to servers.
references:
- https://www.microsoft.com/security/blog/2022/04/04/springshell-rce-vulnerability-guidance-for-protecting-against-and-detecting-cve-2022-22965/
- https://github.com/TheGejr/SpringShell
- https://www.tenable.com/blog/spring4shell-faq-spring-framework-remote-code-execution-vulnerability
tags:
  analytic_story:
  - Spring4Shell CVE-2022-22965
  asset_type: Web Server
  confidence: 80
  cve:
  - CVE-2022-22965
  impact: 90
  message: A suspicious URL has been requested against $dest$ by $src$, related to
    web shell activity.
  mitre_attack_id:
  - T1505.003
  - T1505
  - T1190
  - T1133
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: src
    type: IP Address
    role:
    - Attacker
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _time
  - Web.http_method
  - Web.url
  - Web.url_length
  - Web.src
  - Web.dest
  - Web.http_user_agent
  risk_score: 72
  security_domain: network
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1190/spring4shell/spring4shell_nginx.log
    source: /var/log/nginx/access.log
    sourcetype: nginx:plus:kv