CVE-2023-4421

NameCVE-2023-4421
DescriptionThe 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3634-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
nss (PTS)jessie, jessie (lts)2:3.26-1+debu8u17vulnerable
stretch (security)2:3.26.2-1.1+deb9u5vulnerable
stretch (lts), stretch2:3.26.2-1.1+deb9u6vulnerable
buster2:3.42.1-1+deb10u5vulnerable
buster (security)2:3.42.1-1+deb10u7fixed
bullseye (security), bullseye2:3.61-1+deb11u3fixed
bookworm2:3.87.1-1fixed
sid, trixie2:3.98-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
nsssourcebuster2:3.42.1-1+deb10u7DLA-3634-1
nsssource(unstable)2:3.61-1

Notes

https://bugzilla.mozilla.org/show_bug.cgi?id=1651411
https://bugzilla.redhat.com/show_bug.cgi?id=2238677
https://hg.mozilla.org/projects/nss/rev/fc05574c739947d615ab0b2b2b564f01c922eccd

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