Information Exposure Affecting nss-sysinit package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.06% (30th percentile)

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  • Snyk IDSNYK-RHEL6-NSSSYSINIT-5898955
  • published13 Sept 2023
  • disclosed13 Sept 2023

Introduced: 13 Sep 2023

CVE-2023-4421  (opens in a new tab)
CWE-208  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:6 nss-sysinit.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nss-sysinit package and not the nss-sysinit package as distributed by RHEL. See How to fix? for RHEL:6 relevant fixed versions and status.

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.

CVSS Scores

version 3.1