PT-2023-6220 · Mozilla+3 · Network Security Services+3

Hubert Kario · Published 2023-09-13 · Updated 2024-04-11 · CVE-2023-4421

Positive Technologies (AI Summary)

CVSS v2.0

7.8

High

Base vector

AV:N/AC:L/Au:N/C:C/I:N/A:N

Name of the Vulnerable Software and Affected Versions Network Security Services (NSS) versions prior to 3.61

Description The issue is related to the implementation of the PKCS#1 v1.5 standard in the NSS library, which was leaking information useful for mounting Bleichenbacher-like attacks through timing side-channel. This allowed an attacker to decrypt a previously intercepted PKCS#1 v1.5 ciphertext or forge a signature using the victim's key by sending a large number of attacker-selected ciphertexts. The problem was fixed by implementing the implicit rejection algorithm.

Recommendations For versions prior to 3.61, update to version 3.61 or later to resolve the issue. As a temporary workaround, consider implementing the implicit rejection algorithm to return a deterministic random message in case invalid padding is detected. Restrict access to the PKCS#1 v1.5 functionality to minimize the risk of exploitation until the update is applied.

Fix

Side Channel Attack

Weakness Enumeration

CWE-208

CWE-203

Related Identifiers

BDU:2023-06929

CVE-2023-4421

DLA-3634-1

USN-6727-1

USN-6727-2

Affected Products

Astra Linux

Linuxmint

Network Security Services

Ubuntu

References · 27

• https://osv.dev/vulnerability/DLA-3634-1 · Vendor Advisory
• https://ubuntu.com/security/CVE-2023-6135 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2023-4421 · Vendor Advisory
• https://mozilla.org/security/advisories/mfsa2023-53 · Vendor Advisory
• https://bdu.fstec.ru/vul/2023-06929 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2023-4421 · Security Note
• https://osv.dev/vulnerability/USN-6727-1 · Vendor Advisory
• https://osv.dev/vulnerability/USN-6727-2 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2023-4421 · Vendor Advisory
• https://ubuntu.com/security/CVE-2023-5388 · Vendor Advisory
• https://ubuntu.com/security/notices/USN-6727-1 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2023-4421 · Vendor Advisory
• https://mozilla.org/en-US/security/advisories/mfsa2023-53 · Vendor Advisory
• https://ubuntu.com/security/notices/USN-6727-2 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2023-4421 · Vendor Advisory