Overview
A user enumeration vulnerability has been identified in Windu CMS, tracked as CVE-2025-59116. This flaw allows attackers to determine the validity of usernames during the login process. By observing subtle differences in error messages, an attacker can distinguish between valid and invalid login attempts, making the system susceptible to brute-force attacks against legitimate user accounts.
The vendor was notified about this issue but did not respond with details of the vulnerability or the vulnerable version range. Version 4.1 has been confirmed as vulnerable. Other versions were not tested and may also be affected.
Technical Details
The vulnerability stems from the login mechanism of Windu CMS. When a user attempts to log in with incorrect credentials, the system provides feedback. The nature of this feedback (specifically, the content or timing of the error message) differs depending on whether the provided username exists within the system. An attacker can leverage these differences to build a list of valid usernames. Once a list of valid usernames is compiled, the attacker can then focus brute-force efforts on those accounts, significantly increasing the chances of a successful account compromise.
CVSS Analysis
Currently, a CVSS score and severity rating are not available (N/A) due to the lack of detailed vendor response and publicly available scoring information. However, the potential impact of this vulnerability should be considered seriously, as it facilitates targeted brute-force attacks.
Possible Impact
Successful exploitation of this user enumeration vulnerability can lead to:
- Account Compromise: Attackers can brute-force passwords for valid user accounts.
- Data Breach: Compromised accounts can provide access to sensitive data stored within the CMS.
- Website Defacement: Attackers may gain administrative access and deface or modify the website.
- Malware Distribution: Compromised accounts could be used to upload and distribute malicious software.
Mitigation and Patch Steps
Since the vendor has not provided a patch or specific mitigation advice, the following steps are recommended:
- Rate Limiting: Implement rate limiting on the login endpoint to slow down brute-force attempts. This can be done at the web server level (e.g., using mod_evasive for Apache or similar modules for other web servers) or through a security plugin.
- Web Application Firewall (WAF): Deploy a WAF to detect and block suspicious login activity and common brute-force attack patterns.
- Multi-Factor Authentication (MFA): Enable MFA for all user accounts to add an extra layer of security, even if the password is compromised.
- Disable User Registration: If possible, disable public user registration to reduce the number of potential target accounts.
- Monitor Login Attempts: Implement monitoring and alerting for failed login attempts to detect potential brute-force attacks early.
- Consider Migration: Evaluate alternative CMS solutions if the lack of vendor support and security updates poses an unacceptable risk.
Important: As only version 4.1 was confirmed vulnerable, upgrading to a newer version (if available) *might* address the issue, but this cannot be guaranteed without official confirmation from the vendor.
