Padding Oracle in Gin

Padding Oracle attacks exploit the way encrypted data is validated, allowing attackers to decrypt ciphertext without knowing the encryption key. In Gin applications, this vulnerability typically appears in two critical areas: cookie-based session management and encrypted token handling.

When Gin uses encrypted cookies for session storage (via github.com/gin-contrib/sessions with cookie stores), the application must decrypt and validate the padding of the encrypted data. If the application reveals whether decryption failed due to invalid padding versus other errors, an attacker can exploit this information to gradually decrypt the cookie contents.