InstaWP Connect <= 0.1.3.6 - Unauthenticated Cryptographic Key Disclosure

The InstaWP Connect – 1-click WP Staging & Migration plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 0.1.3.6 via the (top-level script) function. This is due to the plugin stores its encrypted options file as options-{migrate_key}.txt in wp-content/instawpbackups/ without deploying an index.php or .htaccess to prevent directory listing, exposing the 40-character migrate_key on Apache servers with directory indexing enabled, which allows an attacker to derive the AES-256-CBC passphrase via SHA256(migrate_key), decrypt the options file to recover the api_signature. This makes it possible for unauthenticated attackers to get the database access details and api_signature. Exploitation requires the target WordPress site to be hosted on Apache with directory listing enabled (Options +Indexes) for the wp-content/instawpbackups/ directory, and time limited because it can only be exploited during the migration period.