CVE-2023-0361

Publication date 15 February 2023

Last updated 24 July 2024

Ubuntu priority

Cvss 3 Severity Score

A timing side-channel in the handling of RSA ClientKeyExchange messages was discovered in GnuTLS. This side-channel can be sufficient to recover the key encrypted in the RSA ciphertext across a network in a Bleichenbacher style attack. To achieve a successful decryption the attacker would need to send a large amount of specially crafted messages to the vulnerable server. By recovering the secret from the ClientKeyExchange message, the attacker would be able to decrypt the application data exchanged over that connection.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
gnutls28	23.04 lunar	Fixed 3.7.8-5ubuntu1
	22.10 kinetic	Fixed 3.7.7-2ubuntu2.1
	22.04 LTS jammy	Fixed 3.7.3-4ubuntu1.2
	20.04 LTS focal	Fixed 3.6.13-2ubuntu1.8
	18.04 LTS bionic	Ignored
	16.04 LTS xenial	Ignored
	14.04 LTS trusty	Ignored

Notes

mdeslaur

bionic already contains a sidechannel in RSA decryption because CVE-2018-16868 is not fixed due to it being too intrusive. We will ignore this CVE for bionic and earlier also.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
gnutls28	Upstream: 80a6ce8 Upstream: 4b7ff42

Severity score breakdown

Parameter	Value
Base score	7.4 · High
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

Related Ubuntu Security Notices (USN)

USN-5901-1
GnuTLS vulnerability
28 February 2023