CVE-2025-40668 Overview
CVE-2025-40668 is an incorrect authorization vulnerability [CWE-863] in TCMAN GIM v11, a computerized maintenance management system. A low-privileged authenticated attacker can change the password of arbitrary users by sending a crafted POST request to the /PC/WebService.aspx/validateChangePassword%C3%B1a endpoint. The exploit requires that the PasswordActual parameter be empty, bypassing the current-password verification check that should prevent cross-account password changes.
Critical Impact
Any authenticated user can hijack other accounts, including administrative accounts, by resetting their passwords without knowing the original credentials.
Affected Products
- TCMAN GIM v11.0
- cpe:2.3:a:tcman:gim:11.0:*:*:*:*:*:*:*
- Deployments exposing the /PC/WebService.aspx endpoint to authenticated users
Discovery Timeline
- 2025-06-09 - CVE-2025-40668 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-40668
Vulnerability Analysis
The flaw resides in the password-change web service exposed by TCMAN GIM at /PC/WebService.aspx/validateChangePassword%C3%B1a. The endpoint accepts four parameters: idUser, PasswordActual, PasswordNew, and PasswordNewRepeat. In a properly implemented password-change workflow, the server must verify that the requester owns the account referenced by idUser and that PasswordActual matches the stored credential.
GIM v11 fails to enforce either check when PasswordActual is submitted as an empty value. The service accepts the request, treats the authorization as valid, and overwrites the password associated with idUser. A standard user session is sufficient to trigger the behavior.
Root Cause
The root cause is a broken authorization control classified under [CWE-863]. The server-side handler branches on whether PasswordActual is populated. When the field is empty, the code path that validates the submitter's identity against idUser is skipped, and the password update is applied directly to the targeted account.
Attack Vector
Exploitation requires network access to the GIM web application and a low-privileged account. The attacker authenticates, issues a POST request to the vulnerable method with the target's idUser, an empty PasswordActual, and attacker-chosen values for PasswordNew and PasswordNewRepeat. The attacker then logs in as the victim with the new password.
No verified proof-of-concept code is published. Technical details are described in the INCIBE Notice on Multiple Vulnerabilities.
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Stop Identity AttacksDetection Methods for CVE-2025-40668
Indicators of Compromise
- POST requests to /PC/WebService.aspx/validateChangePassword%C3%B1a where the PasswordActual parameter is empty or absent.
- Password change events where the authenticated session user differs from the idUser parameter in the request body.
- Successful logins from unusual source addresses immediately following a password change event.
Detection Strategies
- Inspect IIS and application logs for calls to the validateChangePassword web method and correlate the session identity with the submitted idUser.
- Deploy a web application firewall rule that blocks requests to the endpoint when PasswordActual is empty.
- Alert on bursts of password-change requests originating from a single authenticated session.
Monitoring Recommendations
- Forward GIM web server logs to a centralized SIEM for continuous analysis and retention.
- Monitor administrative account logins for anomalous source IPs, user-agents, or session times following any password reset.
- Track lockout and failed authentication counters that may indicate attempted account takeover.
How to Mitigate CVE-2025-40668
Immediate Actions Required
- Restrict network access to the GIM web application to trusted internal segments and authenticated VPN users.
- Contact TCMAN to obtain a fixed build of GIM and apply it as soon as available.
- Force a password reset for all GIM accounts, prioritizing administrative users, to invalidate any attacker-set credentials.
Patch Information
No vendor advisory URL is listed in the enriched data. Coordination of this issue was handled through INCIBE-CERT; refer to the INCIBE Notice on Multiple Vulnerabilities and contact TCMAN directly to confirm the patched release that addresses CVE-2025-40668.
Workarounds
- Block the /PC/WebService.aspx/validateChangePassword%C3%B1a endpoint at a reverse proxy or WAF until a patch is applied.
- Enforce a WAF rule that rejects any request to the password-change method where PasswordActual is empty or missing.
- Audit existing accounts, remove unused low-privileged users, and limit application access to the minimum required workforce.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
