CVE-2023-4421
The NSS code used for checking PKCS#1 v1.5 was leaking information useful in mounting Bleichenbacher-like attacks.
Impact
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.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Mozilla | Nss | before 3.6.1 |
Weakness classification
References
- NVD record
- CVE.org record
- https://bugzilla.mozilla.org/show_bug.cgi?id=1651411
- https://www.mozilla.org/security/advisories/mfsa2023-53/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1651411
- https://lists.debian.org/debian-lts-announce/2023/10/msg00039.html
- https://www.mozilla.org/security/advisories/mfsa2023-53/