When sampling randomness for a shared secret, the implementation of Kyber and FrodoKEM, did not check whether crypto/rand.Read() returns an error. In rare deployment cases (error thrown by the Read() function), this could lead to a predictable shared secret.
The tkn20 and blindrsa components did not check whether enough randomness was returned from the user provided randomness source. Typically the user provides crypto/rand.Reader, which in the vast majority of cases will always return the right number random bytes. In the cases where it does not, or the user provides a source that does not, the blinding for blindrsa is weak and integrity of the plaintext is not ensured in tkn20.
Metrics
CVSS Version: 3.1 |
Base Score: 5.3 MEDIUM Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N
l➤ Exploitability Metrics: Attack Vector (AV)* LOCAL Attack Complexity (AC)* HIGH Privileges Required (PR)* NONE User Interaction (UI)* REQUIRED Scope (S)* UNCHANGED