Improper Authentication Bypass in SiteServer SSCMS

Executive Summary

This vulnerability affects SiteServer SSCMS versions up to 7.1.3, 7.2.1, and 7.4.0. It involves improper handling of the LoginController.Submit function in the Admin-Login CAPTCHA component. The issue allows excessive authentication attempts due to a flaw in the isForceLogoutAndLogin argument, which fails to restrict repeated login attempts properly.

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Detection Guidance

The vulnerability is related to improper restriction of excessive authentication attempts in SiteServer SSCMS due to the isForceLogoutAndLogin parameter. To detect it, inspect login logs for repeated failed authentication attempts targeting the Admin-Login CAPTCHA component. Check for unusual patterns in the LoginController.Submit.cs file or monitor excessive login requests to the /Admin/Login endpoint.

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Impact Analysis

An attacker could exploit this to perform brute-force attacks on login credentials, potentially gaining unauthorized access to administrative accounts. The high complexity and difficulty of exploitation reduce the risk but do not eliminate it entirely.

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Mitigation Strategies

Apply the patch from commit df3becb7ebb00a48435418a44fd08a459eb38ace. Implement rate limiting on login attempts for the Admin-Login CAPTCHA component. Review and restrict access to the LoginController.Submit.cs file to prevent unauthorized modifications. Ensure proper validation of the isForceLogoutAndLogin parameter to enforce authentication limits.

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