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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.
It’s better that you guys discuss it in the comments and the click bait effectively makes me click the comments so it all worked out; thanks all.
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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.
If someone can gain physical access to your network, you’re already fucked.
Yeah, if the attacker is in a position to do a MitM attack you have much larger problems than a ssh vulnerability that so far can at most downgrade the encryption of your connection in nearly all cases
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.
So you need an MitM situation to even be able to perfom the attack, and the the attack on works on two ciphers? The article says those ciphers are commonly enabled, but are they default or used in relatively modern distributed versions of openssh?
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.
That means a client could negotiate one or the other on more than half of all internets exposed openssh daemons.
I haven’t got too whizzed up over this, yet, because I have no ssh daemons exposed without a VPN outer wrapper. However it does look nasty.
If you need a man in the middle to exploit this, it’s not that nasty.
So hardened ssh configs following best practice cipher whitelist are unaffected, cool
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.
Long dark winters when everyone is home without socializing with people. You have got to come up with something to survive until the two week summer.
Long dark winters when everyone is home without socializing with people. You have got to come up with something to survive until the two week summer.
I expect better of Ars. Absolute clickbait title and sensationalism. You need a two point MITM and even then it’s not a magic shell.
Great photo illustration
I might just go ahead and change the default port. Problem solved
If someone going through the effort to target you with a MitM over the Internet, that’s not going to stop them.
Just diable the affected ciphers and/or update opened.
Interpreting “a previously-unrecognized weakness in X was just found” as “X just got weaker” is dangerously bad tech writing.
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.
