CVE-2023-4421

2023-12-1217:02:08

mozilla

www.cve.org

nss

pkcs#1 v1.5

bleichenbacher-like attacks

timing side-channel

tls

rsa

implicit rejection algorithm

marvin attack

nss < 3.61

6.6 Medium

AI Score

Confidence

High

0.0005 Low

EPSS

Percentile

18.3%

JSON

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.

CNA Affected

[
  {
    "product": "NSS",
    "vendor": "Mozilla",
    "versions": [
      {
        "lessThan": "3.61",
        "status": "affected",
        "version": "unspecified",
        "versionType": "custom"
      }
    ]
  }
]