WordPress Backup Migration 1.3.7 Remote Command Execution

This Metasploit module exploits an unauthenticated remote command execution vulnerability in WordPress Backup Migration plugin versions 1.3.7 and below. The vulnerability is exploitable through the Content-Dir header which is sent to the /wp-content/plugins/backup-backup/includes/backup-heart.php endpoint. The exploit makes use of a neat technique called PHP Filter Chaining which allows an attacker to prepend bytes to a string by continuously chaining character encoding conversions. This allows an attacker to prepend a PHP payload to a string which gets evaluated by a require statement, which results in command execution.