Re: An additional-auth mechanism for SSH to protect against scanning/probing attacks
Peter Gutmann <[email protected]> Thu, 1 Dec 2022 13:38:05 +0000
| Newsgroups | gmane.ietf.secsh |
|---|---|
| Message-ID | <SY4PR01MB625156A06FFB2C8017BB3206EE149@SY4PR01MB6251.ausprd01.prod.outlook.com> |
Mouse <[email protected]> writes: >> [...] now I'm tempted to see what happens if I respond to connect >> attempts on port 22 with: > >> 220 $servername ESMTP Chuckmail bent over and ready >> +OK POP3 server ready <abcd@$servername> >> OK IMAP/POP3 ready $servername >> 220 FTP Server $servername ready >> SSH-2.0-$server-$version > >Should be amusing, if nothing else! So PuTTY handles it just fine while MobaXterm reports a decryption error, probably because it's hashing the entire mess of initial text rather than just the last line with the SSH ID and getting incorrect encryption keys. Having said that, I don't think anything should be accepting that abomination as an SSH ID even if the spec says they should, it's an abuse of a weird corner case in the spec to send that and expect it to work. Peter.