CVE-2023-48795

MEDIUM EXPLOITED NUCLEI

OpenSSH <9.6 - Open Redirect

Title source: llm
STIX 2.1

Exploitation Summary

CVE-2023-48795 has been observed exploited in the wild (reported by VulnCheck KEV). EIP tracks 5 public exploits from researchers including TrixSec, Mr-Whiskerss, oseasfr. A Nuclei detection template is also available.

AI-analyzed exploit summary This repository contains a Python-based scanner that checks for OpenSSH versions vulnerable to CVE-2023-48795 by querying remote SSH servers. It does not exploit the vulnerability but detects vulnerable versions (pre-9.6).

Description

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.

Exploits (5)

nomisec SCANNER 10 stars
by TrixSec · poc
https://github.com/TrixSec/CVE-2023-48795

This repository contains a Python-based scanner that checks for OpenSSH versions vulnerable to CVE-2023-48795 by querying remote SSH servers. It does not exploit the vulnerability but detects vulnerable versions (pre-9.6).

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: OpenSSH < 9.6
No auth needed
Prerequisites: Network access to target SSH ports · SSH service running on target
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec SCANNER 1 stars
by Mr-Whiskerss · poc
https://github.com/Mr-Whiskerss/SSH-Terrapin-Prefix-Truncation-Weakness-CVE-2023-48795-Checker

This repository contains a Python-based scanner for CVE-2023-48795, which checks SSH servers for vulnerability to the Terrapin attack by analyzing KEXINIT packets for vulnerable cipher/MAC combinations and strict-KEX support. It does not exploit the vulnerability but passively detects it.

Classification
Scanner 100%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: SSH servers (OpenSSH < 9.6, PuTTY < 0.80, libssh < 0.10.6, etc.)
No auth needed
Prerequisites: network access to target SSH server
devstral-2 · analyzed Jun 09, 2026 Full analysis →
nomisec SCANNER
by oseasfr · poc
https://github.com/oseasfr/Scanner_CVE_OpenSSH

This repository contains a Python-based scanner that identifies OpenSSH servers potentially vulnerable to CVE-2023-48795 (Terrapin) and CVE-2024-6387 (regreSSHion) by reading SSH banners and comparing versions. It does not exploit the vulnerabilities but scans for them.

Classification
Scanner 100%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH < 9.6 (CVE-2023-48795), OpenSSH < 9.8p1 (CVE-2024-6387)
No auth needed
Prerequisites: Network access to target SSH ports · SSH service running on target
devstral-2 · analyzed May 31, 2026 Full analysis →
nomisec SCANNER
by fumioryoto · poc
https://github.com/fumioryoto/Terrapin-attack

This repository contains a Python-based scanner for detecting SSH servers vulnerable to the Terrapin attack (CVE-2023-48795). It checks for the presence of vulnerable ciphers and strict key exchange support.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions before 9.6
No auth needed
Prerequisites: network access to target SSH server
devstral-2 · analyzed Mar 22, 2026 Full analysis →
nomisec SCANNER
by Dr0xharakiri · poc
https://github.com/Dr0xharakiri/CVE-2023-48795

This repository contains a Python-based scanner that checks for OpenSSH versions vulnerable to CVE-2023-48795 (Terrapin attack) by extracting SSH banners via netcat. It does not exploit the vulnerability but identifies potentially vulnerable targets.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: OpenSSH versions prior to 9.6
No auth needed
Prerequisites: Network access to target SSH port (default: 22) · Netcat installed on the system
devstral-2 · analyzed Feb 18, 2026 Full analysis →

Nuclei Templates (1)

OpenSSH Terrapin Attack - Detection
MEDIUMVERIFIEDby pussycat0x
Shodan: product:"OpenSSH" || product:"openssh" || cpe:"cpe:2.3:a:openbsd:openssh"

References (139)

Core 139
Core References
Mailing List, Mitigation mailing-list
http://www.openwall.com/lists/oss-security/2023/12/20/3
Issue Tracking vendor-advisory
https://www.debian.org/security/2023/dsa-5586
Issue Tracking vendor-advisory
https://www.debian.org/security/2023/dsa-5588
Third Party Advisory vendor-advisory
https://security.gentoo.org/glsa/202312-16
Third Party Advisory vendor-advisory
https://security.gentoo.org/glsa/202312-17
Mailing List, Third Party Advisory mailing-list
https://lists.debian.org/debian-lts-announce/2024/01/msg00013.html
Mailing List, Third Party Advisory mailing-list
https://lists.debian.org/debian-lts-announce/2024/01/msg00014.html
Mailing List, Third Party Advisory mailing-list
http://seclists.org/fulldisclosure/2024/Mar/21
Mailing List, Third Party Advisory mailing-list
https://lists.debian.org/debian-lts-announce/2024/04/msg00016.html

Scores

CVSS v3 5.9
EPSS 0.5166
EPSS Percentile 98.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

VulnCheck KEV 2025-02-05
CWE
CWE-354
Status published
Products (50)
9bis/kitty < 0.76.1.13
apache/sshd < 2.11.0
apache/sshj < 0.37.0
apple/macos 14.0 - 14.4
asyncssh_project/asyncssh < 2.14.2
bitvise/ssh_client < 9.33
bitvise/ssh_server < 9.32
connectbot/sshlib < 2.2.22
crates/thrussh < 0.35.1
crates.io/russh 0 - 0.40.2crates.io
... and 40 more
Published Dec 18, 2023
Tracked Since Feb 18, 2026