CVE-2023-4421

Affected: Mozilla NSS

The NSS code used for checking PKCS#1 v1.5 was leaking information useful in mounting Bleichenbacher-like attacks. Both the overall correctness of the padding as well as the length of the encrypted message was leaking through timing side-channel. By sending large number of attacker-selected ciphertexts, the attacker would be able to decrypt a previously intercepted PKCS#1 v1.5 ciphertext (for example, to decrypt a TLS session that used RSA key exchange), or forge a signature using the victim's key. The issue was fixed by implementing the implicit rejection algorithm, in which the NSS returns a deterministic random message in case invalid padding is detected, as proposed in the Marvin Attack paper. This vulnerability affects NSS < 3.61.

USN-6727-1 — nss vulnerabilities

Affected: Ubuntu:20.04:LTS: nss, Ubuntu:22.04:LTS: nss

It was discovered that NSS incorrectly handled padding when checking PKCS#1 certificates. A remote attacker could possibly use this issue to perform Bleichenbacher-like attacks and recover private data. This issue only affected Ubuntu 20.04 LTS. (CVE-2023-4421)

It was discovered that NSS had a timing side-channel when performing RSA decryption. A remote attacker could possibly use this issue to recover private data. (CVE-2023-5388)

It was discovered that NSS had a timing side-channel when using certain NIST curves. A remote attacker could possibly use this issue to recover private data. (CVE-2023-6135)

The NSS package contained outdated CA certificates. This update refreshes the NSS package to version 3.98 which includes the latest CA certificate bundle and other security improvements.

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CVE-2023-4421

USN-6727-1 — nss vulnerabilities