CVE-2021-37597: 
WordPress vulnerability analysis and mitigation

The WP Cerber Security plugin for WordPress, versions prior to 8.9.3, contained a vulnerability (CVE-2021-37597) that allowed attackers to bypass two-factor authentication (2FA). This security flaw was discovered by Ilyass El Hadi from Mandiant and was publicly disclosed on August 19, 2021. The vulnerability specifically affected the plugin's multi-factor authentication mechanism, impacting WordPress installations using WP Cerber Security for additional authentication layers (Mandiant Disclosure, WPScan).

The vulnerability stemmed from improper validation of HTTP parameters during the authentication process. When users authenticate, they are normally required to enter a 4-digit PIN code sent via email. However, the security flaw could be exploited by manipulating the wordpressloggedin_[hash] cookie in several ways: deleting it entirely, removing a character from it, or adding a character to it. This manipulation allowed unauthorized access to protected pages and directories without providing the required PIN code (Mandiant Disclosure).

The vulnerability was classified as having a high impact, as it allowed attackers to access restricted information and functionality without completing the full authentication process. Successful exploitation could lead to unauthorized access to areas protected by multi-factor authentication (Mandiant Disclosure).

The vulnerability was addressed in WP Cerber Security version 8.9.3, released on August 16, 2021. Users were advised to update to this version or later to protect against potential exploitation. The fix was implemented following coordination between WordPress and the WP Cerber development team (Mandiant Disclosure).