PT-2023-7786 · Panic+26 · Transmit5+29
Fabian Bäumer
+2
·
Published
2023-12-18
·
Updated
2026-04-27
·
CVE-2023-48795
CVSS v2.0
7.1
High
| Vector | AV:N/AC:H/Au:N/C:C/I:C/A:N |
Name of the Vulnerable Software and Affected Versions
OpenSSH versions prior to 9.6
libssh2 versions through 1.11.0
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
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
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
the Russh crate before 0.40.2 for Rust
Description
The SSH transport protocol with certain OpenSSH extensions is vulnerable to a prefix truncation attack, known as the Terrapin attack. This attack allows a man-in-the-middle attacker to strip an arbitrary number of messages right after the initial key exchange, breaking SSH extension negotiation and downgrading connection security. The attack works by injecting arbitrary SSH MSG IGNORE messages during the initial key exchange and removing the same number of messages just after the initial key exchange has concluded. This is possible due to missing authentication of the excess SSH MSG IGNORE messages and the fact that the implicit sequence numbers used within the SSH protocol are only checked after the initial key exchange.
Recommendations
To mitigate this vulnerability, update to OpenSSH 9.6 or later, and consider implementing "strict kex" to alter the SSH handshake and prevent man-in-the-middle attacks. Additionally, temporarily disable the affected algorithms and use unaffected alternatives like AES-GCM until patches are available. For each affected version, apply the corresponding update or patch:
- OpenSSH: Update to version 9.6 or later.
- libssh2: Update to version 1.11.1 or later.
- Maverick Synergy Java SSH API: Update to version 3.1.0-SNAPSHOT or later.
- Dropbear: Update to version 2022.84 or later.
- Ssh in Erlang/OTP: Update to version 5.1.1 or later.
- PuTTY: Update to version 0.80 or later.
- AsyncSSH: Update to version 2.14.2 or later.
- golang.org/x/crypto: Update to version 0.17.0 or later.
- libssh: Update to version 0.10.6 or later.
- Thorn Tech SFTP Gateway: Update to version 3.4.6 or later.
- Tera Term: Update to version 5.1 or later.
- Paramiko: Update to version 3.4.0 or later.
- jsch: Update to version 0.2.15 or later.
- SFTPGo: Update to version 2.5.6 or later.
- Netgate pfSense Plus: Update to version 23.09.2 or later.
- Netgate pfSense CE: Update to version 2.7.3 or later.
- HPN-SSH: Update to version 18.2.1 or later.
- ProFTPD: Update to version 1.3.8b or later.
- ORYX CycloneSSH: Update to version 2.3.4 or later.
- NetSarang XShell 7: Update to Build 0144 or later.
- CrushFTP: Update to version 10.6.0 or later.
- ConnectBot SSH library: Update to version 2.2.22 or later.
- Apache MINA sshd: Update to version 2.11.1 or later.
- sshj: Update to version 0.37.1 or later.
- TinySSH: Update to version 20230102 or later.
- trilead-ssh2: Update to version 6402 or later.
- LANCOM LCOS and LANconfig: Apply the latest security patches.
- FileZilla: Update to version 3.66.4 or later.
- Nova: Update to version 11.8 or later.
- PKIX-SSH: Update to version 14.4 or later.
- SecureCRT: Update to version 9.4.3 or later.
- Transmit5: Update to version 5.10.4 or later.
- Win32-OpenSSH: Update to version 9.5.0.0p1-Beta or later.
- WinSCP: Update to version 6.2.2 or later.
- Bitvise SSH Server: Update to version 9.32 or later.
- Bitvise SSH Client: Update to version 9.33 or later.
- KiTTY: Update to version 0.76.1.14 or later.
- the net-ssh gem: Update to version 7.2.1 or later for Ruby.
- the mscdex ssh2 module: Update to version 1.15.0 or later for Node.js.
- the thrussh library: Update to version 0.35.1 or later for Rust.
- the Russh crate: Update to version 0.40.2 or later for Rust.
Exploit
Fix
Insufficient Verification of Data Authenticity
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Related Identifiers
Affected Products
Alt Linux
Almalinux
Apache Mina Sshd
Astra Linux
Bitvise Ssh Client
Bitvise Ssh Server
Centos
Debian
Erlang/Otp
Freebsd
Ibm Aix
Keycloak
Lancom Lcos/Lanconfig
Linuxmint
Apple Macos
Maverick Synergy Java Ssh Api
Netsarang Xshell 7
Netgate Pfsense Ce
Netgate Pfsense Plus
Oryx Cyclonessh
Red Hat
Red Os
Rocky Linux
Securecrt
Suse
Tera Term
Thorn Tech Sftp Gateway
Transmit5
Ubuntu
Golang.Org/X/Crypto