CVE-2025-41015: Tcman Gim Information Disclosure Flaw

CVE-2025-41015 Overview

CVE-2025-41015 is a user enumeration vulnerability affecting TCMAN GIM v11 version 20250304. This vulnerability allows an unauthenticated attacker to determine whether a user exists on the system. The vulnerability is exploitable through the pda:username parameter with soapaction GetUserQuestionAndAnswer in the /WS/PDAWebService.asmx endpoint. With a CVSS 4.0 score of 6.9 (Medium severity), this information disclosure flaw can serve as a reconnaissance step for more targeted attacks against valid user accounts.

Critical Impact

Unauthenticated attackers can enumerate valid usernames through the SOAP web service, enabling targeted credential attacks such as password spraying or phishing campaigns against confirmed user accounts.

Affected Products

• TCMAN GIM v11 version 20250304
• TCMAN GIM (all versions matching cpe:2.3:a:tcman:gim::::::::)

Discovery Timeline

• 2025-12-02 - CVE-2025-41015 published to NVD
• 2025-12-03 - Last updated in NVD database

Technical Details for CVE-2025-41015

Vulnerability Analysis

This vulnerability is classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). The TCMAN GIM application exposes a SOAP-based web service at /WS/PDAWebService.asmx that implements a GetUserQuestionAndAnswer method. When an attacker sends requests to this endpoint with different values in the pda:username parameter, the application's response behavior differs based on whether the supplied username exists in the system.

The CVSS 4.0 vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N indicates:

• Attack Vector (AV:N): Network-accessible, requiring no local access
• Attack Complexity (AC:L): Low complexity to exploit
• Privileges Required (PR:N): No authentication needed
• User Interaction (UI:N): No user interaction required
• Confidentiality Impact (VC:L): Low confidentiality impact through information disclosure

The EPSS score of 0.082% (24th percentile) indicates a relatively low probability of exploitation in the wild, though the vulnerability remains a concern for organizations running affected versions.

Root Cause

The root cause of this vulnerability lies in improper error handling and response differentiation in the GetUserQuestionAndAnswer SOAP action. The application fails to implement consistent response behavior regardless of whether a username exists, allowing attackers to infer user existence based on varying response messages, HTTP status codes, or response timing.

Proper implementation should return identical responses for both valid and invalid usernames to prevent enumeration attacks. The absence of rate limiting on the affected endpoint further exacerbates the issue by allowing automated enumeration of large username lists.

Attack Vector

The attack vector is network-based, targeting the SOAP web service endpoint /WS/PDAWebService.asmx. An attacker can exploit this vulnerability by sending crafted SOAP requests with the GetUserQuestionAndAnswer action and iterating through potential usernames in the pda:username parameter.

The exploitation process involves sending SOAP requests to the vulnerable endpoint and analyzing the responses. When a valid username is supplied, the application returns a different response (potentially including the security question) compared to when an invalid username is provided. This differential response allows attackers to build a list of valid user accounts.

For detailed technical information about this vulnerability, refer to the INCIBE-CERT advisory.

Detection Methods for CVE-2025-41015

Indicators of Compromise

• High volume of requests to /WS/PDAWebService.asmx from a single source IP
• Multiple SOAP requests with GetUserQuestionAndAnswer action containing different username values
• Sequential or dictionary-based username patterns in the pda:username parameter
• Abnormal access patterns to the PDA web service endpoint outside normal business hours

Detection Strategies

Organizations should implement monitoring for anomalous activity targeting the TCMAN GIM web services. Web Application Firewalls (WAF) can be configured to detect and alert on high-frequency requests to the /WS/PDAWebService.asmx endpoint. SIEM solutions should correlate multiple failed authentication attempts following enumeration activity against discovered usernames.

Network-based detection should focus on identifying patterns consistent with automated scanning tools, including:

• Rapid succession of SOAP requests to the vulnerable endpoint
• Requests originating from known malicious IP ranges or anonymization services
• User-Agent strings associated with scanning tools

Monitoring Recommendations

Implement real-time logging and alerting for all requests to the /WS/PDAWebService.asmx endpoint. Configure threshold-based alerts for request volumes exceeding normal operational patterns. Enable detailed logging of SOAP action parameters to facilitate forensic analysis. Consider implementing honeypot usernames that, when queried, trigger immediate security alerts.

How to Mitigate CVE-2025-41015

Immediate Actions Required

• Review and apply any available patches or updates from TCMAN for GIM v11
• Implement rate limiting on the /WS/PDAWebService.asmx endpoint to slow enumeration attempts
• Deploy Web Application Firewall rules to detect and block automated enumeration requests
• Restrict access to the PDA web service to authorized IP ranges where possible
• Enable comprehensive logging on the affected endpoint for security monitoring

Patch Information

Consult the INCIBE-CERT advisory for the latest patch information from TCMAN. Organizations should contact TCMAN directly for updated versions of GIM that address this vulnerability. Until a patch is available, implement the compensating controls described in the workarounds section.

Workarounds

If immediate patching is not possible, organizations should implement compensating controls to reduce the risk of exploitation:

Network-level controls can restrict access to the vulnerable endpoint. Configure your web server or reverse proxy to limit access to /WS/PDAWebService.asmx to only authorized IP addresses or networks. Implement rate limiting to restrict the number of requests per IP address within a defined time window.

Additionally, consider implementing CAPTCHA or similar challenge-response mechanisms for the GetUserQuestionAndAnswer functionality to prevent automated enumeration. Monitor for suspicious activity and be prepared to temporarily disable the affected endpoint if active exploitation is detected.