CVE-2025-40661: DM Corporative CMS Auth Bypass Flaw

CVE-2025-40661 Overview

CVE-2025-40661 is an Insecure Direct Object Reference (IDOR) vulnerability in DM Corporative CMS developed by acc (DMacroWeb). The flaw resides in the /administer/selectionnode/selection.asp endpoint, where an unauthenticated attacker can manipulate the option parameter by setting its value to 0, 1, or 2 to access the private administrative area. The vulnerability is classified under CWE-639: Authorization Bypass Through User-Controlled Key.

Critical Impact

Remote, unauthenticated attackers can bypass authorization checks and access restricted CMS resources by modifying a single URL parameter, exposing private administrative content over the network.

Affected Products

• DM Corporative CMS (vendor: acc / DMacroWeb)
• All versions referenced in the INCIBE Security Notice
• Deployments exposing /administer/selectionnode/selection.asp to untrusted networks

Discovery Timeline

• 2025-06-10 - CVE-2025-40661 published to the National Vulnerability Database
• 2025-10-22 - Last updated in NVD database

Technical Details for CVE-2025-40661

Vulnerability Analysis

The vulnerability stems from missing authorization enforcement on the selection.asp endpoint within the /administer/selectionnode/ path. The application uses the option query parameter as a direct reference to backend resources without validating whether the requesting session has permission to view them. Setting option=0, option=1, or option=2 returns content reserved for authenticated administrators.

IDOR vulnerabilities like this one allow attackers to enumerate resources by modifying predictable identifiers in URLs or request bodies. Because the affected endpoint resides inside the /administer/ directory, the exposed data is administrative in nature, increasing the operational risk for affected sites.

Root Cause

The root cause is an authorization control gap mapped to [CWE-639]. The CMS validates the structure of the option parameter but does not verify that the current user is authorized to access the referenced object. Authentication state and role membership are not enforced server-side before returning the protected resource.

Attack Vector

The attack vector is purely network-based and requires no authentication, no user interaction, and no elevated privileges. An attacker issues an HTTP GET request to /administer/selectionnode/selection.asp with the option parameter set to 0, 1, or 2. The server responds with private administrative content that should require valid session credentials.

Refer to the INCIBE Security Notice for the coordinated disclosure details and the broader set of vulnerabilities reported against DM Corporative CMS.

Detection Methods for CVE-2025-40661

Indicators of Compromise

• Unauthenticated HTTP requests to /administer/selectionnode/selection.asp containing option=0, option=1, or option=2
• Web server access logs showing successful 200 OK responses to /administer/ paths from sessions without prior authentication
• Sequential enumeration of the option parameter from a single source IP within short time windows

Detection Strategies

• Inspect IIS or web server logs for direct access to administrative ASP endpoints from external IP ranges
• Deploy WAF rules that flag requests to /administer/ paths lacking a valid administrator session cookie
• Correlate access to selection.asp with the absence of preceding authentication events to identify authorization bypass attempts

Monitoring Recommendations

• Forward web server and application logs to a centralized analytics platform for retention and query
• Establish baseline traffic patterns for /administer/ paths and alert on deviations from authenticated user behavior
• Track repeated parameter enumeration patterns targeting option, id, and similar reference parameters across CMS endpoints

How to Mitigate CVE-2025-40661

Immediate Actions Required

• Restrict external access to /administer/ paths using IP allowlists, VPN, or reverse proxy authentication
• Audit web server logs for prior unauthenticated requests to selection.asp with option=0, option=1, or option=2
• Contact DMacroWeb (acc) for a vendor patch and apply it as soon as it becomes available

Patch Information

At the time of publication, no vendor patch URL is referenced in the NVD entry. Operators should monitor the INCIBE Security Notice and direct vendor communications from DMacroWeb for remediation updates covering CVE-2025-40661.

Workarounds

• Block requests to /administer/selectionnode/selection.asp at the WAF or reverse proxy when the request lacks an authenticated administrator session
• Enforce server-side authorization checks on all ASP endpoints under /administer/ using session validation before returning resources
• Rename or relocate administrative endpoints behind authenticated reverse proxy paths until a vendor fix is deployed

# Example NGINX reverse proxy rule restricting administrative paths
location ~* ^/administer/ {
    allow 10.0.0.0/8;       # internal admin network
    deny all;
    proxy_pass http://dm_corporative_cms_backend;
}