SB2024041082 - Ubuntu update for nss

Description

This security bulletin contains information about 3 secuirty vulnerabilities.

1) Covert Timing Channel (CVE-ID: CVE-2023-4421)

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to 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.

2) Covert timing channel (CVE-ID: CVE-2023-5388)

The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists due to insufficient fix for #VU84108 (CVE-2023-4421). A remote attacker can perform Marvin attack and gain access to sensitive information.

3) Observable discrepancy (CVE-ID: CVE-2023-6135)

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to a side-channel attack in multiple NSS NIST curves, known as "Minerva". A remote attacker can recover the private key and decrypt data passed between server and client.

Remediation

Install update from vendor's website.

References

• https://ubuntu.com/security/notices/USN-6727-1