CVE-2023-48795 (https://terrapin-attack.com/): 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 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, and PuTTY before 0.80; and there could be effects on Bitvise SSH through 9.31, AsyncSSH through 2.14.1, libssh through 0.10.5, and golang.org/x/crypto through 2023-12-17.
I've used the following command to mitigate on the client side: sed -i "1i Ciphers -$(ssh -Q cipher | grep -e chacha20-poly1305@openssh.com -e -cbc | paste -d, -s -)" ~/.ssh/config In my case, the following line got added before the first line of the file: Ciphers -3des-cbc,aes128-cbc,aes192-cbc,aes256-cbc,chacha20-poly1305@openssh.com
CVE-2023-46445 and CVE-2023-46446 are issues in AsyncSSH, which Gentoo has not packaged, so I believe they are irellevant here. Only CVE-2023-48795 refers to the Terrapin vulnerability in the SSH protocol itself that affects pretty much every SSH implementation.
Why was kde proj CCed here at all?
(In reply to Andreas Sturmlechner from comment #3) > Why was kde proj CCed here at all? Looks it it might have carried over from this bug: https://bugs.gentoo.org/920291
