CVE-2015-6830 in phpMyAdmin
Summary
by MITRE
libraries/plugins/auth/AuthenticationCookie.class.php in phpMyAdmin 4.3.x before 4.3.13.2 and 4.4.x before 4.4.14.1 allows remote attackers to bypass a multiple-reCaptcha protection mechanism against brute-force credential guessing by providing a correct response to a single reCaptcha.
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Analysis
by VulDB Data Team • 08/20/2025
The vulnerability identified as CVE-2015-6830 affects phpMyAdmin versions 4.3.x before 4.3.13.2 and 4.4.x before 4.4.14.1, specifically within the authentication mechanism located in libraries/plugins/auth/AuthenticationCookie.class.php. This flaw represents a critical security weakness that undermines the intended protection measures designed to prevent automated brute-force attacks against administrative interfaces. The vulnerability stems from a design flaw in how the application handles multiple reCaptcha verification checks, allowing attackers to bypass the intended security controls through a single valid reCaptcha response.
The technical implementation of this vulnerability involves the improper validation of reCaptcha responses within the authentication cookie handling component. When phpMyAdmin implements multiple reCaptcha checks as a security measure against brute-force attacks, the system fails to properly validate that all required reCaptcha challenges have been successfully completed before granting access. This creates a scenario where an attacker can provide a single correct reCaptcha response and subsequently attempt multiple credential guesses without additional reCaptcha verification. The flaw essentially allows bypassing the layered security controls that should have required multiple independent reCaptcha validations.
The operational impact of this vulnerability is severe as it effectively neutralizes the reCaptcha-based brute-force protection mechanism that administrators rely on to secure their database management interfaces. Attackers can now systematically attempt credential guessing attacks without the additional barrier that multiple reCaptcha challenges should provide, significantly increasing the success probability of automated login attempts. This vulnerability directly violates the principle of defense in depth by allowing bypass of multiple security controls that were implemented to protect against credential guessing attacks, which aligns with CWE-305 weakness classification related to authentication mechanisms.
This vulnerability exposes phpMyAdmin installations to increased risk of unauthorized access through credential brute-forcing attacks, potentially leading to complete database compromise. The flaw enables attackers to perform repeated login attempts without proper reCaptcha validation, making it easier to discover valid administrative credentials through automated tools. From an ATT&CK framework perspective, this vulnerability maps to technique T1110.003 (Credential Stuffing) and T1110.001 (Password Guessing) as it removes the effective barriers that should prevent these attack vectors. Organizations using vulnerable versions of phpMyAdmin face significant risk of unauthorized database access, data exfiltration, and potential lateral movement within their network infrastructure.
The recommended mitigation strategy involves upgrading to phpMyAdmin version 4.3.13.2 or 4.4.14.1, which contain the necessary patches to properly validate multiple reCaptcha responses. Administrators should also implement additional security measures such as IP address restrictions, failed login attempt throttling, and network-level access controls to provide additional layers of protection. The vulnerability demonstrates the importance of proper input validation and authentication flow control in web applications, emphasizing the need for comprehensive security testing of authentication mechanisms to prevent similar bypass scenarios in other security controls.