CVE-2024-5956

Executive Summary

CVE-2024-5956 is an authentication bypass vulnerability in Trellix IPS Manager that allows unauthenticated remote attackers to bypass authentication and gain partial data access. The vulnerability is characterized by the attacker receiving garbage data in responses, indicating a potential memory disclosure or improper session handling. With a CVSS score of 6.5 (Medium), the attack complexity is low, requires no privileges, and no user interaction, making it exploitable over the network. The EPSS score is 0.0%, suggesting low exploitation activity in the wild, but the lack of a patch increases risk for unpatched deployments.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – Vulnerability does not affect other components.
• Confidentiality (C): Low (L) – Partial data access, mostly garbage data.
• Integrity (I): None (N) – No data modification.
• Availability (A): None (N) – No denial of service.

Threat Level: Medium. The vulnerability is easy to exploit but yields limited useful data. However, the lack of a patch and potential for memory disclosure could lead to information leakage.

Deep Dive & Mechanics

The vulnerability resides in the authentication mechanism of Trellix IPS Manager. An unauthenticated attacker can send specially crafted requests that bypass the authentication check, allowing access to certain endpoints or data. The response contains garbage data, likely due to uninitialized memory or improper session validation. This suggests the application fails to properly validate session tokens or user credentials, allowing arbitrary access to internal data structures.

The attack vector is network-based, requiring no prior access. The low complexity indicates that standard tools or scripts can exploit this. The partial data access, while mostly garbage, could include sensitive information if memory is not properly sanitized.

Vulnerable vs. Patched Code

Since no patch is available, a comparison cannot be made. However, based on the description, the vulnerable code likely lacks proper authentication checks in certain API endpoints or session handling routines. A patched version would implement robust authentication validation, such as verifying session tokens against a secure store and ensuring memory is cleared before reuse.

Exploitation & Lab Setup

Red Team

1. Setup: Deploy a vulnerable Trellix IPS Manager instance in an isolated lab environment.
2. Reconnaissance: Use Shodan dorks to identify exposed instances.
3. Exploitation: Craft HTTP requests to bypass authentication. Example using curl:

   curl -v -X GET "http://target-ip:port/endpoint" -H "Cookie: session=invalid"
   

   Observe the response for garbage data or partial data leakage.
4. Data Extraction: Automate the process to collect any useful data from responses.

Blue Team

1. Detection: Monitor for anomalous HTTP requests to authentication endpoints.
2. Honeypot: Deploy a fake Trellix IPS Manager to capture exploitation attempts.
3. Logging: Enable detailed logging of all authentication attempts and responses.
4. Mitigation: Implement network segmentation to limit exposure of the IPS Manager.

Indicators of Compromise (IOCs)

• Network: HTTP requests to /login or /api endpoints with invalid session cookies.
• Response: Responses containing binary garbage data or unexpected memory dumps.
• Logs: Failed authentication attempts followed by successful data retrieval without valid credentials.
• File: Unusual memory dumps or core files on the server.

Detection Engineering

YARA Rule

rule CVE_2024_5956_Trellix_IPS_Manager_Auth_Bypass {
    meta:
        description = "Detects exploitation attempts for CVE-2024-5956"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-5956"
    strings:
        $s1 = "Trellix IPS Manager" ascii wide nocase
        $s2 = "garbage" ascii wide nocase
        $s3 = "authentication bypass" ascii wide nocase
    condition:
        any of them
}

Sigma Rule

title: CVE-2024-5956 Trellix IPS Manager Authentication Bypass
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects HTTP requests attempting to bypass authentication on Trellix IPS Manager
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem: '/login'
        sc-status: 200
        cs(User-Agent): '*'
    condition: selection
falsepositives:
    - Legitimate users with valid sessions
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-5956 Trellix IPS Manager Auth Bypass Attempt"; flow:to_server; content:"GET"; http_method; content:"/login"; http_uri; content:"session="; http_cookie; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Disable remote access to Trellix IPS Manager if not required. Use VPN or firewall rules to restrict access.
• Workaround: Implement additional authentication layers, such as IP whitelisting or multi-factor authentication.
• Patch: Monitor Trellix for official patches. Apply when available.
• Long-term: Conduct a security audit of the authentication mechanism. Consider replacing with a more secure solution.

Valters IT
Securing Digital Frontiers