CVE-2023-48795

The SSH transport protocol with certain OpenSSH extensions, found in
OpenSSH before 9.6 and other products, allows remote attackers to bypass
integrity checks such that some packets are omitted (from the extension
negotiation message), and a client and server may consequently end up with
a connection for which some security features have been downgraded or
disabled, aka a Terrapin attack. This occurs because the SSH Binary Packet
Protocol (BPP), implemented by these extensions, mishandles the handshake
phase and mishandles use of sequence numbers. For example, there is an
effective attack against SSH’s use of ChaCha20-Poly1305 (and CBC with
Encrypt-then-MAC). The bypass occurs in [email protected] and
(if CBC is used) the [email protected] MAC algorithms. This also affects
Maverick Synergy Java SSH API before 3.1.0-SNAPSHOT, Dropbear through
2022.83, Ssh before 5.1.1 in Erlang/OTP, PuTTY before 0.80, AsyncSSH before
2.14.2, golang.org/x/crypto before 0.17.0, libssh before 0.10.6, libssh2
through 1.11.0, Thorn Tech SFTP Gateway before 3.4.6, Tera Term before 5.1,
Paramiko before 3.4.0, jsch before 0.2.15, SFTPGo before 2.5.6, Netgate
pfSense Plus through 23.09.1, Netgate pfSense CE through 2.7.2, HPN-SSH
through 18.2.0, ProFTPD before 1.3.8b (and before 1.3.9rc2), ORYX
CycloneSSH before 2.3.4, NetSarang XShell 7 before Build 0144, CrushFTP
before 10.6.0, ConnectBot SSH library before 2.2.22, Apache MINA sshd
through 2.11.0, sshj through 0.37.0, TinySSH through 20230101, trilead-ssh2
6401, LANCOM LCOS and LANconfig, FileZilla before 3.66.4, Nova before 11.8,
PKIX-SSH before 14.4, SecureCRT before 9.4.3, Transmit5 before 5.10.4,
Win32-OpenSSH before 9.5.0.0p1-Beta, WinSCP before 6.2.2, Bitvise SSH
Server before 9.32, Bitvise SSH Client before 9.33, KiTTY through
0.76.1.13, the net-ssh gem 7.2.0 for Ruby, the mscdex ssh2 module before
1.15.0 for Node.js, the thrussh library before 0.35.1 for Rust, and the
Russh crate before 0.40.2 for Rust.

Bugs

• <https://github.com/golang/go/issues/64784&gt;
• <https://github.com/paramiko/paramiko/issues/2337&gt;
• <https://github.com/libssh2/libssh2/issues/1290&gt;

Notes