GHSA-rh3w-4ccx-prf9 Admidio has Inverted 2FA Reset Authorization Check that Lets Group Leaders Strip Admin TOTP

• Packagist admidio/admidio: < 5.0.9 → fixed in 5.0.9

Summary A logic error in Admidio's two-factor authentication reset inverts the authorization check. Non-admin users cannot remove their own TOTP configuration, but they can remove other users' TOTP, including administrators. A group leader with profile edit rights on an admin account can strip that admin's 2FA. Details In `modules/profile/two_factor_authentication.php` at line 84, the authorization check uses an inverted condition: ```php // modules/profile/two_factor_authentication.php line 84 if (!($gCurrentUser->isAdministrator() || $gCurrentUserId !== $userId)) { throw new AdmException('SYS_NO_RIGHTS'); } ``` By De Morgan's law, this condition evaluates as: • Blocks when: `NOT isAdministrator() AND $gCurrentUserId === $userId` • In practice: blocks non-admins from resetting their OWN 2FA • Passes: non-admins resetting OTHER users' 2FA (the opposite of the intended behavior) The intended logic should block non-admins from resetting other users' 2FA. The `!==` operator on line 84 should be `===`. A group leader who holds `hasRightEditProfile()` permission on an admin user (checked earlier in the flow) can exploit this to strip 2FA from administrator accounts, reducing their security to password-only authentication. Proof of Concept 1. As `testuser` (a non-admin group leader with edit rights on admin profiles), send: ```http POST /adm_program/modules/profile/two_factor_authentication.php HTTP/1.1 Content-Type: application/x-www-form-urlencoded Cookie: ADMIDIO_..._SESSION_ID= mode=reset&user_uuid= ``` Result: the server removes 2FA from the admin account. 2. As `testuser`, attempt to reset their own 2FA: ```http POST /adm_program/modules/profile/two_factor_authentication.php HTTP/1.1 Content-Type: application/x-www-form-urlencoded Cookie: ADMIDIO_..._SESSION_ID= mode=reset&user_uuid= ``` Result: `SYS_NO_RIGHTS` error. The user cannot reset their own 2FA. This confirms the authorization logic is inverted. Impact A group leader (or any user with profile edit rights on an admin) can disable two-factor authentication on administrator accounts. This degrades admin account security to password-only, opening the door to credential stuffing or brute force attacks without a 2FA barrier. Recommended Fix Change `!==` to `===` on line 84 of `modules/profile/two_factor_authentication.php`: ```php // Fixed condition: block non-admins from resetting OTHER users' 2FA if (!($gCurrentUser->isAdministrator() || $gCurrentUserId === $userId)) { throw new AdmException('SYS_NO_RIGHTS'); } ``` --- *Found by aisafe.io*