CVE-2025-40658: DM Corporative CMS Auth Bypass Flaw

CVE-2025-40658 Overview

An Insecure Direct Object Reference (IDOR) vulnerability has been discovered in DM Corporative CMS. This vulnerability allows an unauthenticated attacker to access private administrative areas by manipulating the option parameter in the /administer/selectionnode/framesSelection.asp endpoint. By setting the option parameter to values 0, 1, or 2, attackers can bypass access controls and gain unauthorized access to restricted functionality within the content management system.

Critical Impact

Unauthenticated attackers can bypass authorization controls to access private administrative sections of DM Corporative CMS, potentially exposing sensitive configuration data and administrative functionality.

Affected Products

• DM Corporative CMS (all versions)
• Acc DM Corporative CMS
• DMacroweb CMS implementations

Discovery Timeline

• 2025-06-10 - CVE-2025-40658 published to NVD
• 2025-10-22 - Last updated in NVD database

Technical Details for CVE-2025-40658

Vulnerability Analysis

This vulnerability represents a classic Insecure Direct Object Reference (IDOR) flaw categorized under CWE-639 (Authorization Bypass Through User-Controlled Key). The vulnerability exists in the frame selection functionality of DM Corporative CMS's administrative interface. The application fails to properly validate user authorization before processing requests to the framesSelection.asp endpoint, allowing any user to access protected resources by directly manipulating request parameters.

The vulnerable endpoint /administer/selectionnode/framesSelection.asp accepts an option parameter that determines which administrative view or functionality is rendered. When this parameter is set to specific values (0, 1, or 2), the application returns content from protected administrative areas without verifying that the requesting user has appropriate privileges.

Root Cause

The root cause of this vulnerability lies in improper access control implementation within the ASP application. The framesSelection.asp script relies solely on parameter values to determine content rendering rather than implementing server-side session validation or role-based access control checks. This design flaw allows attackers to bypass authentication entirely by crafting direct requests with known parameter values.

The application appears to trust client-supplied input for authorization decisions, violating the fundamental security principle that authorization checks must be performed server-side for every protected resource request.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker can exploit this vulnerability by sending crafted HTTP requests directly to the vulnerable endpoint. The attack flow involves:

1. Identifying the vulnerable endpoint at /administer/selectionnode/framesSelection.asp
2. Manipulating the option parameter to values 0, 1, or 2
3. Receiving unauthorized access to private administrative content
4. Potentially chaining with other vulnerabilities for deeper system compromise

The vulnerability manifests in the parameter handling logic of the framesSelection.asp endpoint. When processing requests, the application fails to validate whether the requesting user has administrative privileges before serving protected content. Attackers can simply modify the URL parameter to access different administrative views. For technical implementation details, refer to the INCIBE Security Notice.

Detection Methods for CVE-2025-40658

Indicators of Compromise

• Unusual access patterns to /administer/selectionnode/framesSelection.asp from unauthenticated sessions
• HTTP requests containing option=0, option=1, or option=2 parameters from external IP addresses
• Web server logs showing sequential parameter enumeration attempts against administrative endpoints
• Access to administrative ASP pages without corresponding authentication events

Detection Strategies

• Implement web application firewall (WAF) rules to monitor and alert on direct access attempts to /administer/ paths from unauthenticated sources
• Configure intrusion detection systems to flag requests with parameter manipulation patterns targeting the framesSelection.asp endpoint
• Deploy log correlation rules to identify sessions accessing administrative resources without prior authentication events
• Enable detailed request logging for all ASP endpoints within the /administer/ directory structure

Monitoring Recommendations

• Monitor web server access logs for requests to /administer/selectionnode/framesSelection.asp with varying option parameter values
• Configure real-time alerting for any access to administrative paths from IP addresses not on an approved allowlist
• Implement session tracking to correlate administrative page access with valid authentication tokens
• Review access logs periodically for patterns indicating reconnaissance or exploitation attempts

How to Mitigate CVE-2025-40658

Immediate Actions Required

• Restrict access to the /administer/ directory to authorized IP addresses only using firewall rules or web server configuration
• Implement authentication checks at the web server level for all administrative endpoints
• Review and audit all user access to the CMS administrative interface for signs of unauthorized access
• Consider taking the administrative interface offline until proper access controls can be implemented

Patch Information

Consult the vendor (Acc) for official patches or updated versions of DM Corporative CMS that address this IDOR vulnerability. Review the INCIBE Security Notice for additional guidance on remediation steps and any available vendor communications.

Workarounds

• Implement IP-based access restrictions to limit administrative interface access to trusted networks only
• Deploy a reverse proxy or web application firewall to enforce authentication before requests reach the vulnerable endpoint
• Modify ASP scripts to include session validation checks at the beginning of each administrative page
• Disable or rename the vulnerable framesSelection.asp file if the functionality is not critical to operations

# IIS URL Rewrite rule to block unauthenticated access to admin paths
# Add to web.config in the site root
<system.webServer>
  <rewrite>
    <rules>
      <rule name="Block Admin Access" stopProcessing="true">
        <match url="^administer/.*" />
        <conditions>
          <add input="{REMOTE_ADDR}" pattern="^192\.168\.1\." negate="true" />
        </conditions>
        <action type="CustomResponse" statusCode="403" statusReason="Forbidden" />
      </rule>
    </rules>
  </rewrite>
</system.webServer>