CVE-2023-4421
Published: 12 December 2023
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.
Notes
Author | Note |
---|---|
mdeslaur | The fix for this issue was incomplete, leading to CVE-2023-5388 |
Priority
Status
Package | Release | Status |
---|---|---|
nss Launchpad, Ubuntu, Debian |
bionic |
Needed
|
focal |
Released
(2:3.98-0ubuntu0.20.04.1)
|
|
jammy |
Not vulnerable
(2:3.68.2-0ubuntu1.2)
|
|
lunar |
Not vulnerable
(2:3.87.1-1)
|
|
mantic |
Not vulnerable
(2:3.92-1)
|
|
noble |
Not vulnerable
(2:3.92-1)
|
|
trusty |
Needed
|
|
upstream |
Released
(3.61)
|
|
xenial |
Needed
|
|
Patches: upstream: https://hg.mozilla.org/projects/nss/rev/fc05574c739947d615ab0b2b2b564f01c922eccd |
Severity score breakdown
Parameter | Value |
---|---|
Base score | 6.5 |
Attack vector | Network |
Attack complexity | Low |
Privileges required | Low |
User interaction | None |
Scope | Unchanged |
Confidentiality | High |
Integrity impact | None |
Availability impact | None |
Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |