• Even the researcher who reported this doesn’t go as far as this headline.

    “I am an admin, should I drop everything and fix this?”

    Probably not.

    The attack requires an active Man-in-the-Middle attacker that can intercept and modify the connection’s traffic at the TCP/IP layer. Additionally, we require the negotiation of either ChaCha20-Poly1305, or any CBC cipher in combination with Encrypt-then-MAC as the connection’s encryption mode.

    […]

    “So how practical is the attack?”

    The Terrapin attack requires an active Man-in-the-Middle attacker, that means some way for an attacker to intercept and modify the data sent from the client or server to the remote peer. This is difficult on the Internet, but can be a plausible attacker model on the local network.

    https://terrapin-attack.com/

    • It definitely receives more clicks. I’ve posted this link here a day ago, but arstechnicas title is more engaging. My first thought was whether there’s been another vulnerability found.

      That said, the headline isn’t as bad as it could’ve been.

  • Since he doesn’t mention it in his ‘fantastic’ reporting, OpenSSH 9.6 was released Monday that will patch this attack. Also, since he doesn’t mention it, if on the Internet, the MITM would have to be installed at both end points (client side and server side) to be effective without the patch.

    • Since he doesn’t mention it in his ‘fantastic’ reporting, OpenSSH 9.6 was released Monday that will patch this attack.

      I am tempted to delete this post just for the article’s stupid clickbait headline, but it still will probably cause some people to go update their OpenSSH installs, so… meh.

      Anyone who actually wants to know details of the vulnerability should read the website about it which is obviously much better than this article.

      Also, since he doesn’t mention it, if on the Internet, the MITM would have to be installed at both end points (client side and server side) to be effective without the patch.

      Huh? No. The attacker doesn’t need to be in two places or even near either end per se, they could be located at any fully on-path position between the client and server.

  • Ylönen, who at the time knew little about implementing strong cryptography in code, set out to develop the Secure Shell Protocol (SSH)

    TIL SSH was invented by a Finn. I swear that country has the most awesome per capita of any country on earth.

  • This is the best summary I could come up with:


    Once in place, this piece of dedicated hardware surreptitiously inhaled thousands of user names and passwords before it was finally discovered.

    Ylönen, who at the time knew little about implementing strong cryptography in code, set out to develop the Secure Shell Protocol (SSH) in early 1995, about three months after the discovery of the password sniffer.

    As one of the first network tools to route traffic through an impregnable tunnel fortified with a still-esoteric feature known as “public key encryption,” SSH quickly caught on around the world.

    Today, it’s hard to overstate the importance of the protocol, which underpins the security of apps used inside millions of organizations, including cloud environments crucial to Google, Amazon, Facebook, and other large companies.

    Now, nearly 30 years later, researchers have devised an attack with the potential to undermine, if not cripple, cryptographic SSH protections that the networking world takes for granted.

    The attack targets the BPP, short for Binary Packet Protocol, which is designed to ensure that adversaries with an active position can’t add or drop messages exchanged during the handshake.


    The original article contains 658 words, the summary contains 178 words. Saved 73%. I’m a bot and I’m open source!

    • you missed this part:

      For Terrapin to be viable, the connection it interferes with also must be secured by either “ChaCha20-Poly1305” or “CBC with Encrypt-then-MAC,” both of which are cipher modes added to the SSH protocol (in 2013 and 2012, respectively). A scan performed by the researchers found that 77 percent of SSH servers exposed to the Internet support at least one of the vulnerable encryption modes, while 57 percent of them list a vulnerable encryption mode as the preferred choice.