CVE-2024-34399

Executive Summary

CVE-2024-34399 is a critical authentication bypass vulnerability in BMC Remedy Mid Tier version 7.6.04. An unauthenticated remote attacker can access any user account without a password. This product is end-of-life and unsupported, meaning no official patch will be released. The vulnerability is publicly known and poses a severe risk to any remaining deployments.

Supply Chain & Package Security

This vulnerability is not related to a package manager (NPM, PyPI, Go, Ruby). It is a standalone enterprise application (BMC Remedy Mid Tier) that is end-of-life. No supply chain implications exist.

CVSS Breakdown & Threat Level

• CVSS Score: 9.8 (Critical)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

Threat Level: Critical. The vulnerability allows complete account takeover without authentication, leading to full system compromise.

Deep Dive & Mechanics

The vulnerability resides in the authentication mechanism of BMC Remedy Mid Tier 7.6.04. The application fails to properly validate user credentials, allowing an attacker to bypass the login process entirely. By sending a specially crafted request (likely manipulating session tokens or authentication headers), the attacker can impersonate any user, including administrative accounts.

The root cause is a missing authentication check in the session handling or user validation logic. Since the product is unsupported, no code fix is available. The vulnerability is trivial to exploit and requires no prior knowledge or access.

Vulnerable vs. Patched Code

No patched version exists. The vulnerable code is in the authentication module of BMC Remedy Mid Tier 7.6.04. A hypothetical fix would involve implementing proper credential validation and session management.

Vulnerable Code (Conceptual):

// Vulnerable: No password check
public User authenticate(String username, String password) {
    User user = userDAO.findByUsername(username);
    if (user != null) {
        return user; // Bypasses password validation
    }
    return null;
}

Patched Code (Hypothetical):

// Patched: Proper password validation
public User authenticate(String username, String password) {
    User user = userDAO.findByUsername(username);
    if (user != null && user.getPassword().equals(hash(password))) {
        return user;
    }
    return null;
}

Exploitation & Lab Setup

Red Team

Exploit:

import requests

target = "http://target-ip:port/arsys/forms/login"
# Craft a request that bypasses authentication
# Example: Manipulate session cookie or use a null password
headers = {"Cookie": "session=admin; password="}
response = requests.get(target, headers=headers)
if "Welcome" in response.text:
    print("Authentication bypass successful")

Lab Setup:

1. Deploy BMC Remedy Mid Tier 7.6.04 in a controlled environment.
2. Use a tool like Burp Suite to intercept and modify login requests.
3. Send requests with empty password fields or manipulated session tokens.
4. Observe successful login without valid credentials.

Blue Team

Detection:

• Monitor for login attempts with empty or null password fields.
• Alert on unusual session creation patterns (e.g., rapid creation of admin sessions).
• Use the Sigma rule below to detect exploitation attempts.

Mitigation:

• Immediately isolate or decommission the affected system.
• If decommissioning is not possible, implement a WAF rule to block requests with missing or empty authentication parameters.
• Restrict network access to the application using firewall rules.

Indicators of Compromise (IOCs)

• Network: HTTP requests to /arsys/forms/login with empty password fields or manipulated session cookies.
• Logs: Successful login events without corresponding password validation.
• System: Unauthorized user sessions, especially for privileged accounts.

Detection Engineering

YARA Rule

rule CVE_2024_34399_Authentication_Bypass {
    meta:
        description = "Detects exploitation attempts for CVE-2024-34399"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $s1 = "password=" nocase
        $s2 = "session=" nocase
        $s3 = "login" nocase
    condition:
        all of them
}

Sigma Rule

title: CVE-2024-34399 Authentication Bypass Attempt
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects attempts to exploit authentication bypass in BMC Remedy Mid Tier
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem: '/arsys/forms/login'
        cs-uri-query|contains: 'password='
    condition: selection
falsepositives:
    - Legitimate login attempts with empty password (unlikely)
level: critical

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-34399 Authentication Bypass Attempt"; flow:to_server; content:"/arsys/forms/login"; http_uri; content:"password="; http_uri; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Decommission: Remove BMC Remedy Mid Tier 7.6.04 from production immediately.
2. Isolate: If decommissioning is not possible, isolate the system from the network.
3. Upgrade: Migrate to a supported version of BMC Remedy (if available) or an alternative solution.

Long-Term Actions:

• Implement a vulnerability management program to identify and retire end-of-life software.
• Use network segmentation and access controls to limit exposure of legacy systems.
• Monitor for any signs of compromise using the provided detection rules.

Workarounds (Temporary):

• Deploy a WAF with a custom rule to block requests with empty password fields.
• Restrict access to the application via VPN or IP whitelisting.

Valters IT
Securing Your Digital Frontier