CVE-2016-5838 in WordPress
Summary
by MITRE
WordPress before 4.5.3 allows remote attackers to bypass intended password-change restrictions by leveraging knowledge of a cookie.
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Analysis
by VulDB Data Team • 05/08/2019
WordPress versions prior to 4.5.3 contained a critical security flaw that allowed remote attackers to circumvent intended password change restrictions through the exploitation of cookie knowledge. This vulnerability specifically targeted the password reset functionality within the WordPress authentication system, creating a pathway for unauthorized users to modify account credentials without proper authorization. The flaw emerged from insufficient validation mechanisms that relied on cookie-based session identifiers, which could be manipulated or guessed by malicious actors.
The technical implementation of this vulnerability stemmed from WordPress's password reset mechanism failing to properly verify the authenticity of session tokens associated with password change requests. When users initiated password reset operations, the system generated temporary tokens stored in cookies that should have been validated against the user's actual session state. However, the validation process was flawed, allowing attackers who possessed knowledge of valid cookie values to bypass the normal authentication checks required for password modifications. This weakness enabled attackers to perform unauthorized password changes on user accounts, potentially leading to complete account compromise and unauthorized access to sensitive data.
The operational impact of this vulnerability was substantial as it could be exploited remotely without requiring any prior authentication credentials or privileged access to the system. Attackers could leverage this flaw to gain unauthorized control over user accounts, potentially accessing confidential information, modifying content, or using compromised accounts for further attacks within the WordPress environment. The vulnerability affected all WordPress installations running versions earlier than 4.5.3, making it particularly dangerous as it impacted a large portion of the web hosting ecosystem that relied on WordPress for content management. This weakness could be exploited through various attack vectors including social engineering to obtain cookie values, session hijacking techniques, or by exploiting other vulnerabilities that might have exposed cookie information.
The vulnerability aligns with CWE-384, which addresses session fixation and token management issues in web applications, and demonstrates poor adherence to secure session handling principles outlined in the OWASP Top Ten security framework. From an ATT&CK perspective, this vulnerability maps to T1110.003 (Credential Access: Password Guessing) and T1566 (Initial Access: Phishing) as it enables attackers to obtain valid credentials through manipulation of existing session tokens rather than traditional brute force or social engineering methods. Organizations affected by this vulnerability were advised to immediately upgrade to WordPress version 4.5.3 or later, which implemented proper token validation mechanisms and strengthened session management protocols. Additional mitigations included implementing proper cookie security settings such as HttpOnly and Secure flags, enforcing strict session timeout policies, and monitoring for unusual authentication activities. The incident highlighted the critical importance of robust session management and token validation in web applications, particularly in content management systems that handle sensitive user data and authentication processes.