| Name | CVE-2021-36367 |
| Description | PuTTY 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). |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DLA-3794-1 |
| Debian Bugs | 990901 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| putty (PTS) | jessie, jessie (lts) | 0.63-10+deb8u2 | vulnerable |
| stretch (security), stretch (lts), stretch | 0.67-3+deb9u1 | vulnerable |
| buster (security), buster, buster (lts) | 0.74-1+deb11u1~deb10u2 | fixed |
| bullseye | 0.74-1+deb11u2 | fixed |
| bullseye (security) | 0.74-1+deb11u1 | fixed |
| bookworm | 0.78-2+deb12u2 | fixed |
| bookworm (security) | 0.78-2+deb12u1 | fixed |
| sid, trixie | 0.81-3 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| putty | source | jessie | (unfixed) | end-of-life | | |
| putty | source | buster | 0.74-1+deb11u1~deb10u1 | | DLA-3794-1 | |
| putty | source | bullseye | 0.74-1+deb11u1 | | | |
| putty | source | (unstable) | 0.75-3 | | | 990901 |
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