CVE-2021-36367

NameCVE-2021-36367
DescriptionPuTTY through 0.75 proceeds with establishing an SSH session even if it has never sent a substantive authentication response. This makes it easier for an attacker-controlled SSH server to present a later spoofed authentication prompt (that the attacker can use to capture credential data, and use that data for purposes that are undesired by the client user).
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3794-1
Debian Bugs990901

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
putty (PTS)jessie, jessie (lts)0.63-10+deb8u2vulnerable
stretch (security), stretch (lts), stretch0.67-3+deb9u1vulnerable
buster (security), buster, buster (lts)0.74-1+deb11u1~deb10u2fixed
bullseye0.74-1+deb11u2fixed
bullseye (security)0.74-1+deb11u1fixed
bookworm0.78-2+deb12u2fixed
bookworm (security)0.78-2+deb12u1fixed
sid, trixie0.82-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
puttysourcejessie(unfixed)end-of-life
puttysourcebuster0.74-1+deb11u1~deb10u1DLA-3794-1
puttysourcebullseye0.74-1+deb11u1
puttysource(unstable)0.75-3990901

Notes

[stretch] - putty <no-dsa> (Minor issue)
https://git.tartarus.org/?p=simon/putty.git;a=commit;h=1dc5659aa62848f0aeb5de7bd3839fecc7debefa
hard to backport code, it is only a mitigation of some kind of attack not a fix

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