CVE-2020-8771: 
WordPress vulnerability analysis and mitigation

The Time Capsule plugin before version 1.21.16 for WordPress contained a critical authentication bypass vulnerability (CVE-2020-8771). The vulnerability allowed unauthorized users to gain administrator access to WordPress sites by exploiting a logical flaw in the code. Any request containing the specific string 'IWP_JSON_PREFIX' would cause the client to be automatically logged in as the first administrator account on the system (WPScan, WebARX).

The vulnerability resided in the wptc-cron-functions.php file (line 12) where the parse_request function called decode_server_request_wptc. This function checked if the raw POST payload contained a specific string ('IWP_JSON_PREFIX'). When detected, it triggered the wptc_login_as_admin function, which automatically logged the requester in as the first available administrator account without requiring any authentication. The vulnerability received a CVSS score of 9.8 (Critical) and was classified as CWE-287 (Improper Authentication) (WPScan).

The vulnerability allowed attackers to bypass authentication completely and gain unauthorized administrative access to WordPress sites running the affected plugin. This level of access would give attackers full control over the website, including the ability to modify content, install malicious plugins, or potentially compromise the entire system (WebARX).

The vulnerability was patched in version 1.21.16 of the WP Time Capsule plugin. The fix involved removing several calls to the wptc_login_as_admin function and implementing proper payload authenticity verification before processing requests. Users were advised to update to the latest version immediately (WebARX).

The developer responded quickly to the initial vulnerability report, releasing patches the very next day after being notified. Security companies like WebARX (now Patchstack) added specific firewall rules to protect their customers against this vulnerability, though they noted that cloud-based firewalls might have difficulty distinguishing between malicious and legitimate traffic (WebARX).