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)
|
|
| 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 |