Information Exposure Affecting nss-softokn-freebl package, versions <0:3.53.1-6.48.amzn1
Snyk CVSS
Threat Intelligence
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Test your applications- Snyk ID SNYK-AMZN201803-NSSSOFTOKNFREEBL-6033697
- published 25 Oct 2023
- disclosed 12 Dec 2023
Introduced: 25 Oct 2023
CVE-2023-4421 Open this link in a new tabHow to fix?
Upgrade Amazon-Linux:2018.03
nss-softokn-freebl
to version 0:3.53.1-6.48.amzn1 or higher.
This issue was patched in ALAS-2023-1858
.
NVD Description
Note: Versions mentioned in the description apply only to the upstream nss-softokn-freebl
package and not the nss-softokn-freebl
package as distributed by Amazon-Linux
.
See How to fix?
for Amazon-Linux:2018.03
relevant fixed versions and status.
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.