openssh (1:9.2p1-2+deb12u2) bookworm-security; urgency=medium
* Cherry-pick from upstream:
- [CVE-2023-28531] ssh-add(1): when adding smartcard keys to
ssh-agent(1) with the per-hop destination constraints (ssh-add -h ...)
added in OpenSSH 8.9, a logic error prevented the constraints from
being communicated to the agent. This resulted in the keys being added
without constraints. The common cases of non-smartcard keys and keys
without destination constraints are unaffected. This problem was
reported by Luci Stanescu (closes: #1033166).
- [CVE-2023-48795] ssh(1), sshd(8): implement protocol extensions to
thwart the so-called "Terrapin attack" discovered by Fabian Bäumer,
Marcus Brinkmann and Jörg Schwenk. This attack allows a MITM to effect
a limited break of the integrity of the early encrypted SSH transport
protocol by sending extra messages prior to the commencement of
encryption, and deleting an equal number of consecutive messages
immediately after encryption starts. A peer SSH client/server would
not be able to detect that messages were deleted.
- [CVE-2023-51384] ssh-agent(1): when adding PKCS#11-hosted private keys
while specifying destination constraints, if the PKCS#11 token
returned multiple keys then only the first key had the constraints
applied. Use of regular private keys, FIDO tokens and unconstrained
keys are unaffected.
- [CVE-2023-51385] ssh(1): if an invalid user or hostname that contained
shell metacharacters was passed to ssh(1), and a ProxyCommand,
LocalCommand directive or "match exec" predicate referenced the user
or hostname via %u, %h or similar expansion token, then an attacker
who could supply arbitrary user/hostnames to ssh(1) could potentially
perform command injection depending on what quoting was present in the
user-supplied ssh_config(5) directive. ssh(1) now bans most shell
metacharacters from user and hostnames supplied via the command-line.
-- Colin Watson <email address hidden> Tue, 19 Dec 2023 14:51:56 +0000
