CVE-2025-41015: TCMAN GIM User Enumeration – Is Your System Exposed?

Overview

CVE-2025-41015 identifies a user enumeration vulnerability within TCMAN GIM v11, specifically version 20250304. This flaw allows an unauthenticated attacker to probe the system and determine if a particular user account exists. This information, while seemingly minor, can be a critical first step in a larger attack, such as a brute-force password attempt or targeted phishing campaign.

Technical Details

The vulnerability is located in the /WS/PDAWebService.asmx endpoint. By manipulating the pda:username parameter in conjunction with the soapaction GetUserQuestionAndAnswer, an attacker can send requests to the server. The server’s response will differ depending on whether the provided username exists. This difference can be subtle but detectable, enabling the attacker to systematically enumerate valid usernames on the TCMAN GIM system.

Here’s a simplified example of a potential request:

            
            POST /WS/PDAWebService.asmx HTTP/1.1
            Host: your_tcman_gim_server
            Content-Type: text/xml; charset=utf-8
            SOAPAction: "http://tempuri.org/GetUserQuestionAndAnswer"

            <?xml version="1.0" encoding="utf-8"?>
            <soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
              <soap:Body>
                <GetUserQuestionAndAnswer xmlns="http://tempuri.org/">
                  <pda:username>valid_username</pda:username>
                </GetUserQuestionAndAnswer>
              </soap:Body>
            </soap:Envelope>
            
        

An attacker would then compare the response to a similar request with a non-existent username. The differences in response time, content length, or specific error messages can reveal the existence of the user.

CVSS Analysis

Currently, the CVSS score for CVE-2025-41015 is marked as N/A, implying the severity hasn’t been formally assessed or considered negligible by the reporting parties. However, the lack of a formal CVSS score doesn’t negate the potential risk. User enumeration, even without a high CVSS score, provides valuable information to attackers and significantly lowers the barrier to entry for more severe attacks.

Possible Impact

The primary impact of this vulnerability is user enumeration. While not directly leading to system compromise, knowing valid usernames allows attackers to:

• Targeted Password Attacks: Focus brute-force attacks on known usernames.
• Spear Phishing: Craft more convincing phishing emails by using valid user information.
• Information Gathering: Combine enumerated usernames with other publicly available data to build a profile of the organization’s user base.

These activities can substantially increase the likelihood of a successful breach.

Mitigation or Patch Steps

To mitigate this vulnerability, take the following steps:

1. Apply the Patch: The most effective solution is to apply the official patch provided by TCMAN GIM, if available. Contact TCMAN support for the latest updates.
2. Implement Rate Limiting: Implement rate limiting on the /WS/PDAWebService.asmx endpoint to restrict the number of requests an attacker can make within a given timeframe. This makes user enumeration significantly more difficult.
3. Input Validation: Enhance input validation on the pda:username parameter. Ensure that the system does not provide distinct responses for valid and invalid usernames. Sanitize the input to prevent unexpected behavior.
4. Web Application Firewall (WAF): Deploy a Web Application Firewall (WAF) with rules to detect and block suspicious requests targeting the vulnerable endpoint.
5. Monitor Logs: Regularly monitor system logs for unusual activity targeting the /WS/PDAWebService.asmx endpoint.

References

• INCIBE-CERT Advisory