CVE-2024-1817: Demososo DM Auth Bypass Vulnerability

CVE-2024-1817 Overview

CVE-2024-1817 is a critical authentication bypass vulnerability discovered in Demososo DM Enterprise Website Building System versions up to 2022.8. The vulnerability exists in the dmlogin function within the indexDM_load.php file, specifically in the Cookie Handler component. By manipulating the is_admin argument with the input value y, an attacker can bypass authentication controls and gain unauthorized administrative access to the system. This vulnerability can be exploited remotely without any prior authentication, making it particularly dangerous for organizations using this content management system.

Critical Impact

Unauthenticated remote attackers can bypass authentication entirely and gain administrative privileges to the website building system, potentially leading to complete system compromise, data theft, and website defacement.

Affected Products

• Demososo DM Enterprise Website Building System up to version 2022.8

Discovery Timeline

• 2024-02-23 - CVE-2024-1817 published to NVD
• 2024-12-17 - Last updated in NVD database

Technical Details for CVE-2024-1817

Vulnerability Analysis

This vulnerability represents a classic improper authentication flaw (CWE-287) where the application fails to properly validate user-supplied cookie values before granting administrative access. The dmlogin function in the Cookie Handler component accepts the is_admin parameter directly from user-controlled cookie data without adequate verification. When this parameter is set to the value y, the application incorrectly assumes the request originates from an authenticated administrator.

The architectural flaw lies in trusting client-side data for authentication decisions. Rather than maintaining server-side session state and validating credentials against a backend authentication store, the application relies on a simple flag in the cookie that attackers can trivially forge.

Root Cause

The root cause of CVE-2024-1817 is the improper implementation of authentication controls in the Cookie Handler component. The dmlogin function within indexDM_load.php does not perform server-side validation of administrative privileges. Instead, it relies on the is_admin cookie value, which can be manipulated by any user with basic knowledge of HTTP cookie mechanics. This design fundamentally violates the principle that authentication decisions should never depend on client-controlled input.

Attack Vector

The attack can be launched remotely over the network without requiring any prior authentication or user interaction. An attacker simply needs to craft an HTTP request with a manipulated cookie containing the is_admin parameter set to y. This grants immediate administrative access to the website building system.

The attack flow involves:

1. Identifying a target Demososo DM Enterprise Website Building System installation
2. Crafting an HTTP request to indexDM_load.php with a cookie containing is_admin=y
3. The dmlogin function processes the cookie and grants administrative privileges
4. The attacker gains full administrative control over the website building system

This vulnerability has been publicly disclosed and exploit details are available through VulDB and the Zhao Jin Note Share technical write-up.

Detection Methods for CVE-2024-1817

Indicators of Compromise

• Unexpected administrative sessions or login events without corresponding valid authentication attempts
• HTTP requests to indexDM_load.php containing the is_admin=y cookie parameter from untrusted sources
• Unusual modifications to website content, configurations, or user accounts
• Access logs showing administrative actions from unfamiliar IP addresses or geographic locations

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing suspicious is_admin cookie manipulation patterns
• Monitor access logs for requests to indexDM_load.php with anomalous cookie values, particularly the is_admin parameter
• Deploy intrusion detection signatures that alert on authentication bypass attempts targeting this specific vulnerability
• Review administrative audit trails for unauthorized changes that coincide with suspicious network activity

Monitoring Recommendations

• Enable verbose logging on the DM Enterprise Website Building System to capture all authentication events and cookie processing
• Implement real-time alerting for administrative access from new or suspicious source IP addresses
• Establish baseline normal administrative behavior and alert on deviations
• Monitor for unauthorized file changes or database modifications that may indicate successful exploitation

How to Mitigate CVE-2024-1817

Immediate Actions Required

• Restrict access to the affected system by placing it behind a VPN or IP whitelist until a patch is applied
• Implement WAF rules to block requests containing manipulated is_admin cookie values
• Review access logs for signs of prior exploitation and audit any changes made to the system
• Consider taking the system offline if it contains sensitive data and cannot be adequately protected

Patch Information

As of the last available information, the vendor (Demososo) was contacted about this vulnerability but did not respond. No official patch has been released. Organizations using the affected software should consider migrating to an alternative content management system that is actively maintained and supported.

For additional technical details, consult the VulDB CTI Report and VulDB advisory.

Workarounds

• Implement network-level access controls to restrict access to the administrative interface to trusted IP addresses only
• Deploy a reverse proxy or WAF that strips or validates the is_admin cookie parameter before forwarding requests
• If source code access is available, modify the dmlogin function in indexDM_load.php to implement proper server-side authentication validation
• Consider migrating to an actively maintained and secure content management platform

# Example WAF rule to block is_admin cookie manipulation (ModSecurity syntax)
SecRule REQUEST_COOKIES:is_admin "^y$" \
    "id:1001,\
    phase:1,\
    deny,\
    status:403,\
    msg:'CVE-2024-1817: Potential authentication bypass attempt detected',\
    log,\
    auditlog"