Vulnerability Details CVE-2023-4421
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 37.2%
CVSS Severity
CVSS v3 Score 6.5
References
Products affected by CVE-2023-4421
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cpe:2.3:a:mozilla:nss:-
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cpe:2.3:a:mozilla:nss:3.1
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cpe:2.3:a:mozilla:nss:3.1.1
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cpe:2.3:a:mozilla:nss:3.2
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cpe:2.3:a:mozilla:nss:3.2.1
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cpe:2.3:a:mozilla:nss:3.3
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cpe:2.3:a:mozilla:nss:3.3.1
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cpe:2.3:a:mozilla:nss:3.3.2
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cpe:2.3:a:mozilla:nss:3.4
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cpe:2.3:a:mozilla:nss:3.4.1
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cpe:2.3:a:mozilla:nss:3.4.2
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cpe:2.3:a:mozilla:nss:3.4.3
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cpe:2.3:a:mozilla:nss:3.6