CVE-2023-4421 | Date: (C)2023-11-29 (M)2024-04-30 |
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.
CVSS Score and Metrics +CVSS Score and Metrics -CVSS V3 Severity: | CVSS V2 Severity: |
CVSS Score : 6.5 | CVSS Score : |
Exploit Score: 2.8 | Exploit Score: |
Impact Score: 3.6 | Impact Score: |
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CVSS V3 Metrics: | CVSS V2 Metrics: |
Attack Vector: NETWORK | Access Vector: |
Attack Complexity: LOW | Access Complexity: |
Privileges Required: LOW | Authentication: |
User Interaction: NONE | Confidentiality: |
Scope: UNCHANGED | Integrity: |
Confidentiality: HIGH | Availability: |
Integrity: NONE | |
Availability: NONE | |
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