The version of FortiWeb installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the FG-IR-23-490 advisory.

  - 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 chacha20-poly1305@openssh.com and     (if CBC is used) the -etm@openssh.com 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. (CVE-2023-48795)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Detections

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Fortinet FortiWeb OpenSSH Terrapin attack (CVE-2023-48795) (FG-IR-23-490)

critical Nessus Plugin ID 209753

Version 1.3

Version 1.2

Version 1.1

Version 1.3 May 14, 2025, 1:49 AM Detection (updated detection logic) Plugin metadata Plugin Feed: 202505140149
Version 1.2 Oct 28, 2024, 10:30 PM CVSS metrics ("Cvssv4 score" set to 9.3) Plugin metadata Plugin Feed: 202410282230
Version 1.1 Oct 27, 2024, 4:20 AM New Plugin Feed: 202410270420