miniOrange OTP Login, Verification and SMS Notifications <= 5.5.5 - Unauthenticated Authentication Bypass via 'mo_wp_login_intent' Parameter

The miniOrange OTP Login, Verification and SMS Notifications plugin for WordPress is vulnerable to Authentication Bypass via the mo_wp_login_intent parameter in all versions up to, and including, 5.5.5. This is due to a missing password-intent guard in the skip_pass_fallback-enabled configuration branch of the mo_by_pass_login() function, which treats administrator role membership alone as sufficient authentication whenever the unauthenticated, unverified POST parameter mo_wp_login_intent is submitted with the value otp, causing mo_get_user() to skip wp_authenticate_username_password() and resolve a WP_User purely from a username lookup. This makes it possible for unauthenticated attackers to log in as any existing administrator account by supplying only a known username and an empty password alongside mo_wp_login_intent=otp, with no password or OTP verification required. Exploitation is conditional on a site administrator having simultaneously enabled the following plugin options: WP Login OTP, Login with Only OTP, Allow Users to Login with Username and Password, and Admin OTP Bypass.

Quoted source text, attributed separately from HOL analysis.