CVE-2025-41336: Canaldenuncia.app Auth Bypass Vulnerability

CVE-2025-41336 Overview

A lack of authorization vulnerability has been detected in CanalDenuncia.app, a whistleblowing and complaint management platform. This vulnerability allows an unauthenticated attacker to access other users' information by sending a specially crafted POST request through the web parameter in /backend/api/buscarConfiguracionParametros.php. The flaw represents a classic Broken Access Control vulnerability (CWE-862: Missing Authorization) where the application fails to properly validate user permissions before returning sensitive configuration data.

Critical Impact

Unauthenticated attackers can access sensitive user information and configuration parameters belonging to other users, potentially exposing confidential whistleblower data and compromising the integrity of the complaint management system.

Affected Products

• CanalDenuncia CanalDenuncia.app (all versions)

Discovery Timeline

• 2025-11-04 - CVE-2025-41336 published to NVD
• 2025-11-05 - Last updated in NVD database

Technical Details for CVE-2025-41336

Vulnerability Analysis

This vulnerability stems from a Missing Authorization flaw in the CanalDenuncia.app backend API. The affected endpoint /backend/api/buscarConfiguracionParametros.php accepts POST requests containing a web parameter but fails to implement proper authorization checks before returning configuration data. This allows any user—authenticated or not—to retrieve information belonging to other users or organizations by manipulating the web parameter value.

The attack requires no authentication and can be executed remotely over the network. An attacker simply needs to identify valid web parameter values to enumerate and extract sensitive configuration parameters. Given the nature of CanalDenuncia.app as a whistleblowing platform, this vulnerability poses significant risks to user privacy and could potentially expose the identities of whistleblowers or the contents of their complaints.

Root Cause

The root cause is the absence of authorization validation in the buscarConfiguracionParametros.php endpoint. The application directly processes the web parameter from incoming POST requests and returns associated configuration data without verifying whether the requester has legitimate access to that information. This represents a violation of the principle of least privilege and proper access control implementation.

Attack Vector

The attack is network-based and requires no user interaction or prior authentication. An attacker can exploit this vulnerability by:

1. Identifying the vulnerable API endpoint at /backend/api/buscarConfiguracionParametros.php
2. Crafting a POST request with a manipulated web parameter
3. Iterating through potential web parameter values to enumerate accessible data
4. Extracting sensitive configuration parameters and user information

The vulnerability allows an attacker to perform horizontal privilege escalation, accessing data belonging to other users at the same privilege level. The attack mechanism involves sending crafted POST requests to the vulnerable endpoint and manipulating the web parameter to access unauthorized configuration data. For detailed technical information, refer to the INCIBE Security Notice.

Detection Methods for CVE-2025-41336

Indicators of Compromise

• Unusual POST requests to /backend/api/buscarConfiguracionParametros.php from external or unknown IP addresses
• High volume of requests to the vulnerable endpoint with varying web parameter values indicating enumeration attempts
• Access log entries showing sequential or randomized web parameter values from a single source
• Unexpected data access patterns where configuration requests span multiple organizational contexts

Detection Strategies

• Implement web application firewall (WAF) rules to monitor and alert on suspicious access patterns to the vulnerable API endpoint
• Deploy application-level logging to track all requests to /backend/api/buscarConfiguracionParametros.php with full parameter capture
• Configure intrusion detection systems (IDS) to identify enumeration attacks targeting the API
• Enable database query auditing to detect unauthorized data access patterns

Monitoring Recommendations

• Review web server access logs for anomalous POST request patterns to backend API endpoints
• Set up real-time alerting for high-frequency requests to the vulnerable endpoint from single IP addresses
• Monitor for parameter tampering attempts in POST requests targeting configuration endpoints
• Establish baseline metrics for normal API usage and alert on deviations

How to Mitigate CVE-2025-41336

Immediate Actions Required

• Restrict access to the /backend/api/buscarConfiguracionParametros.php endpoint using network-level controls until a patch is available
• Implement IP whitelisting for the vulnerable endpoint if possible
• Enable enhanced logging and monitoring for the affected API endpoint
• Review access logs to determine if exploitation has occurred
• Contact the vendor for patch availability information

Patch Information

Organizations should monitor the INCIBE Security Notice for updates on official patches and remediation guidance from the vendor. At the time of this writing, users should apply any available security updates from CanalDenuncia and implement the recommended workarounds until a permanent fix is deployed.

Workarounds

• Implement server-side authorization checks at the web server or reverse proxy level to validate user permissions before allowing access to the vulnerable endpoint
• Deploy a web application firewall (WAF) rule to validate and sanitize the web parameter in POST requests
• Restrict access to the API endpoint to authenticated sessions only using server-side session validation
• Consider temporarily disabling the affected endpoint if it is not critical to business operations

# Example: Apache .htaccess restriction for the vulnerable endpoint
<Files "buscarConfiguracionParametros.php">
    # Restrict access to authenticated sessions only
    # Implement proper authorization at the application level
    Order Deny,Allow
    Deny from all
    # Allow only from trusted internal networks
    Allow from 10.0.0.0/8
    Allow from 192.168.0.0/16
</Files>