Changed fingerprint prompt and duplicate ECDSA host key entries in ~/.ssh/known_hosts

[cyberduck]

59a3ee5 created the issue

I just upgraded to the latest snapshot, and still see this when connecting to hosts of mine

The fingerprint for the ECDSA key sent by the server is bc:d5:5d:36:a4:88:05:47:3d:8c:c0:a1:c2:79:5b:02.

I see this with many Ubuntu 14 VPS hosts which I connect to (not sure if they happen on CentOS hosts)

I do see new lines added to my known_hosts, often with the same signature

|1|9zJQi1kgtbav4hUbTpynNYrOMfk=|3iKfANR/mUwO+nnP30P80h9UPok= ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABABPP3MOu9kj6PR4UaRTZ/2tt2G79lZ6E9vz6ijp8bkcuKoLTkY4K14NO2TWB53IWd6Jw8G+d2MmbL0+DCqZCiNQ==
|1|8VsGSG228W/EYlnCmbJTy8mhtuI=|I92YUz202+wnR29bC6pXyCQLRyM= ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABABPP3MOu9kj6PR4UaRTZ/2tt2G79lZ6E9vz6ijp8bkcuKoLTkY4K14NO2TWB53IWd6Jw8G+d2MmbL0+DCqZCiNQ==

I don't know that I have any fancy setup causing the IP addresses/hostname to be obscured, and wouldn't care if i didn't anymore but right now I'm getting stopped, having to say OK to the changed ECDSA key every time.

I'm not sure if/how this is different from related issues:

• Repeated prompts for RSA fingerprint #8654
• Fingerprint on SFTP differs from SSH #8175
• Wrong host key fingerprint (and not written to ~/.ssh/known_hosts either) #8173

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Attachments

• known_hosts (2.0 KiB)

[cyberduck]

@dkocher commented

Replying to [8867 YesThatAllen]:

I don't know that I have any fancy setup causing the IP addresses/hostname to be obscured, and wouldn't care if i didn't anymore but right now I'm getting stopped, having to say OK to the changed ECDSA key every time.

Hostnames are written to the known_hosts file with hashed representation as this prevents identifying information from being disclosed from the known_hosts file. Refer to the ssh-keygen -H option.

[cyberduck]

@dkocher commented

Can you find any related output in the system.log (/Applications/Utilities/Console.app)? Please try if you can reproduce this error when moving aside the ~/.ssh/known_hosts file, starting from scratch with an empty configuration.

[cyberduck]

59a3ee5 commented

steps to repro on my 10.9.5 box running Cyberduck Version 4.8 (17722)

• mv ~./ssh/known_hosts ~./ssh/known_hosts.sav
• Connect to a saved cyberduck bookmark
• accept the host key -check "always": |1|WLOvbk6OX0BaEO8BRlw1RkFyby8=|TfTJLD9oc1zu0DABUA4Z8MdaZ0g= ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABABPP3MOu9kj6PR4UaRTZ/2tt2G79lZ6E9vz6ijp8bkcuKoLTkY4K14NO2TWB53IWd6Jw8G+d2MmbL0+DCqZCiNQ==
• navigate around, open files using command-k, all is well.
• disconnect
• do other things.. use gitbox to connect to gihub, etc. (4 new lines are created in my known hosts file
• reconnect to the initial host via the bookmark,
• get prompted for the ssh host again.

see today's attached known_hosts file

[cyberduck]

@dkocher commented

I tried to reproduce the issue following your steps (thanks for the detailed instructions!) but couldn't when connecting to an EC2 instance with ECDSA keys followed by connecting to a host with RSA keys. Can you let me know the hostname of TfTJLD9oc1zu0DABUA4Z8MdaZ0g=.

[cyberduck]

59a3ee5 commented

sure, it's www.watchmanmonitoring.com

[cyberduck]

59a3ee5 commented

I should add that I don't think my connections to other RSA hosts made a difference other than to give Cyberduck time to forget about the first key it saved.

it seems to doing the "math" wrong each new connection, not recognizing that the host was already saved.

[cyberduck]

@dkocher commented

I can reproduce this issue when connecting to 173.230.133.218.

[cyberduck]

@dkocher commented

Add test in df68d8e.

[cyberduck]

@dkocher commented

Replying to [comment:11 dkocher]:

Add test in df68d8e.
The test is against OpenSSH_6.2 whereas 173.230.133.218 runs OpenSSH_6.6.1p1.

[cyberduck]

@dkocher commented

Add test in 849fc8e.

[cyberduck]

@dkocher commented

#9092 closed as duplicate.

[cyberduck]

@dkocher commented

Reference upstream #225

[cyberduck]

@dkocher commented

In 18540.

[cyberduck]

@dkocher commented

#9289 closed as duplicate.