Citrix ADC Exploitation CVE-2023-3519

Name:Citrix ADC Exploitation CVE-2023-3519
id:76ac2dcb-333c-4a77-8ae9-2720cfae47a8
version:4
date:2024-10-17
author:Michael Haag, Splunk
status:production
type:Hunting
Description:The following analytic identifies potential exploitation attempts against Citrix ADC related to CVE-2023-3519. It detects POST requests to specific web endpoints associated with this vulnerability by leveraging the Web datamodel. This activity is significant as CVE-2023-3519 involves a SAML processing overflow issue that can lead to memory corruption, posing a high risk. If confirmed malicious, attackers could exploit this to execute arbitrary code, escalate privileges, or disrupt services, making it crucial for SOC analysts to monitor and investigate these alerts promptly.
Data_source:

• -Palo Alto Network Threat

search:| tstats count min(_time) as firstTime max(_time) as lastTime from datamodel=Web where Web.url IN ("*/saml/login","/cgi/samlauth","*/saml/activelogin","/cgi/samlart?samlart=*","*/cgi/logout","/gwtest/formssso?event=start&target=*","/netscaler/ns_gui/vpn/*") Web.http_method=POST by Web.http_user_agent, Web.status 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)`
| `citrix_adc_exploitation_cve_2023_3519_filter`

how_to_implement:This detection requires the Web datamodel to be populated from a supported Technology Add-On like Splunk for Apache, Splunk for Nginx, or Splunk for Palo Alto.
known_false_positives:False positives may be present based on organization use of SAML utilities. Filter, or restrict the analytic to Citrix devices only.
References:
  -https://blog.assetnote.io/2023/07/21/citrix-CVE-2023-3519-analysis/
  -https://support.citrix.com/article/CTX561482/citrix-adc-and-citrix-gateway-security-bulletin-for-cve20233519-cve20233466-cve20233467
  -https://securityintelligence.com/x-force/x-force-uncovers-global-netscaler-gateway-credential-harvesting-campaign/
  -https://support.citrix.com/article/CTX579459/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20234966-and-cve20234967
drilldown_searches:
  :
tags:
  analytic_story:
    - 'Citrix Netscaler ADC CVE-2023-3519'
    - 'CISA AA24-241A'
  cve:
    - 'CVE-2023-3519'
  asset_type:Network
  atomic_guid:
  confidence:50
  impact:90
  message:Possible expliotation of CVE-2023-3519 against $dest$.
  mitre_attack_id:
    - 'T1190'
  observable:
    name:'dest'
    type:'Hostname'
    - role:
      - 'Victim'
  product:
    - 'Splunk Enterprise'
    - 'Splunk Enterprise Security'
    - 'Splunk Cloud'
  risk_score:45
  required_fields:
    - '_time'
    - 'Web.http_method'
    - 'Web.url'
    - 'Web.url_length'
    - 'Web.src'
    - 'Web.dest'
  security_domain:endpoint

tests:
 name:'True Positive Test'
 attack_data:
  data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1190/citrix/citrix-cve20233519.log
  source: pan:threat
  sourcetype: pan:threat
manual_test:None