Nonce Observatory: как превратить цифровые подписи в систему наблюдаемых nonce-инвариантовБольшинство историй про ECDSA/Schnorr nonce звучит одинаково: “повторили nonce — потеряли ключ”. Но реальные дефекты часто тоньше: короткие nonce, частичная утечка битов, смещение, recurrence, window-locality, prefix-семейства,
ChaCha20-Poly1305 is an AEAD cipher, and requires a unique nonce input for every encryption operation. RFC 7539 specifies that the nonce value (IV) should be 96 bits (12 bytes). OpenSSL allows a variable nonce length and front pads the nonce with 0 bytes if it is less than 12 bytes. However it also incorrectly allows a nonce to be set of up to 16 bytes. In this case only the last 12 bytes are significant and any additional leading bytes are ignored. It is a requirement of using this cipher that nonce…
The Essential Blocks plugin for WordPress is vulnerable to unauthorized use of functionality due to a missing capability check on the save function in versions up to, and including, 4.0.6. This makes it possible for subscriber-level attackers to save plugin settings. While a nonce check is present, it is only executed when a nonce is provided. Not providing a nonce results in the nonce verification to be skipped. There is no capability check.
The Essential Blocks plugin for WordPress is vulnerable to unauthorized use of functionality due to a missing capability check on the get function in versions up to, and including, 4.0.6. This makes it possible for subscriber-level attackers to obtain plugin settings. While a nonce check is present, it is only executed when a nonce is provided. Not providing a nonce results in the nonce verification to be skipped. There is no capability check.