Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Tue, 19 Dec 2023 13:31:03 -0800
From: Alan Coopersmith <>
Subject: Re: CVE-2023-48795: Prefix Truncation Attacks in SSH
 Specification (Terrapin Attack)

On 12/18/23 08:08, Fabian Bäumer wrote:
> ### Mitigations
> To mitigate this protocol vulnerability, OpenSSH suggested a so-called "strict 
> kex" which alters the SSH handshake to ensure a Man-in-the-Middle attacker 
> cannot introduce unauthenticated messages as well as convey sequence number 
> manipulation across handshakes. Support for strict key exchange has been added 
> to a variety of SSH implementations, including OpenSSH itself, PuTTY, libssh, 
> and more.
> **Warning: To take effect, both the client and server must support this 
> countermeasure.**

Open source projects I see have implemented this already are:

- AsyncSSH 2.14.2:

- Dropbear git:

- Erlang ssh 5.1.1:

- 0.17.0:

- libssh 0.10.6 and 0.9.8:

- libssh2 git:

- OpenSSH 9.6:

- Paramiko 3.4.0:

- PuTTY 0.80:

- russh 0.40.2:

- SFTPGo 2.5.6:

- ssh2 [node.js/npm] 1.15.0:

- Tera Term 5.1:

- Thrussh 0.35.1:

There's also some open bugs against these open source projects that are not yet handled:

- Apache Mina:

- ProFTPD (mod_sftp):


         -Alan Coopersmith-       
          Oracle Solaris Engineering -

Powered by blists - more mailing lists

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.