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Description

The following analytic identifies attempts to exploit the CVE-2023-46805 and CVE-2024-21887 vulnerabilities in Ivanti Connect Secure. It detects GET requests to the /api/v1/totp/user-backup-code/../../system/system-information URI, which leverage an authentication bypass to access system information. The detection uses the Web datamodel to identify requests with a 200 OK response, indicating a successful exploit attempt. This activity is significant as it reveals potential unauthorized access to sensitive system information. If confirmed malicious, attackers could gain critical insights into the system, facilitating further exploitation and compromise.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Web
  • Last Updated: 2024-05-18
  • Author: Michael Haag, Splunk
  • ID: d51c13dd-a232-4c83-a2bb-72ab36233c5d

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1190 Exploit Public-Facing Application Initial Access
Kill Chain Phase
  • Delivery
NIST
  • DE.AE
CIS20
  • CIS 13
CVE 


1
2
3
4
5
6



| tstats count min(_time) as firstTime max(_time) as lastTime from datamodel=Web where Web.url="*/api/v1/totp/user-backup-code/../../system/system-information*" Web.http_method=GET Web.status=200 by Web.src, Web.dest, Web.http_user_agent, Web.url 
| `drop_dm_object_name("Web")` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `ivanti_connect_secure_system_information_access_via_auth_bypass_filter`

Macros

The SPL above uses the following Macros:

:information_source: ivanti_connect_secure_system_information_access_via_auth_bypass_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.

  • Web.src
  • Web.dest
  • Web.http_user_agent
  • Web.url

How To Implement

This detection requires the Web datamodel to be populated from a supported Technology Add-On like Suricata, Splunk for Apache, Splunk for Nginx, or Splunk for Palo Alto.

Known False Positives

This analytic is limited to HTTP Status 200; adjust as necessary. False positives may occur if the URI path is IP-restricted or externally blocked. It's recommended to review the context of the alerts and adjust the analytic parameters to better fit the specific environment.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
72.0 90 80 Possible exploitation of CVE-2023-46805 and CVE-2024-21887 against $dest$.

: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: 2