web_spring_cloud_function_functionrouter.yml

name: Web Spring Cloud Function FunctionRouter
id: 89dddbad-369a-4f8a-ace2-2439218735bc
version: 3
date: '2024-09-30'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies HTTP POST requests to the Spring Cloud Function endpoint containing "functionRouter" in the URL. It leverages the Web data model to detect these requests based on specific fields such as http_method, url, and http_user_agent. This activity is significant because it targets CVE-2022-22963, a known vulnerability in Spring Cloud Function, which has multiple proof-of-concept exploits available. If confirmed malicious, this activity could allow attackers to execute arbitrary code, potentially leading to unauthorized access, data exfiltration, or further compromise of the affected system.
data_source:
- Splunk Stream HTTP
search: '| tstats count from datamodel=Web where Web.http_method IN ("POST") Web.url="*/functionRouter*" by Web.http_user_agent Web.http_method, Web.url,Web.url_length Web.src, Web.dest Web.status sourcetype | `drop_dm_object_name("Web")` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `web_spring_cloud_function_functionrouter_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://github.com/rapid7/metasploit-framework/pull/16395
- https://github.com/hktalent/spring-spel-0day-poc
drilldown_searches:
- name: View the detection results for - "$dest$"
  search: '%original_detection_search% | search  dest = "$dest$"'
  earliest_offset: $info_min_time$
  latest_offset: $info_max_time$
- name: View risk events for the last 7 days for - "$dest$"
  search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
  earliest_offset: $info_min_time$
  latest_offset: $info_max_time$
tags:
  analytic_story:
  - Spring4Shell CVE-2022-22965
  asset_type: Web Server
  confidence: 60
  cve:
  - CVE-2022-22963
  impact: 70
  message: A suspicious URL has been requested against $dest$ by $src$, related to a vulnerability in Spring Cloud.
  mitre_attack_id:
  - 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: 42
  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/all_functionrouter_http_streams.log
    source: stream:http
    sourcetype: stream:http