2FAuth Reverse Proxy Authentication Bypass Vulnerability

2FAuth is a web app to manage Two-Factor Authentication (2FA) accounts and generate their security codes. A reverse proxy authentication bypass affects versions prior to 8.0.0 when AUTHENTICATION_GUARD=reverse-proxy-guard is enabled.

In this mode, ReverseProxyGuard::user() reads the default REMOTE_USER identity header, or a custom identity header selected by AUTH_PROXY_HEADER_FOR_USER, without confirming that the request originated from a configured trusted proxy.

• A remote client that can reach the application directly can forge the selected identity header and authenticate as an existing user, including an administrator.
• This gives access to stored 2FA secrets and account or application management functions.

The issue is fixed in version 8.0.0.