Dump client ssh key from server side

Question

To investigate on some issue, I need to dump the full ssh key offered by the ssh client to the ssh server.

Up to this point, I tried to

put the parent of all sshd server (belongs to root) LogLevel to DEBUG strace -f (to follow child processes) the root sshd process with large snap window (-s 8192) tcpdump -X (to print ) -s 8192 (to capture 8192 bytes max of each frame) Checking the strace log does not show the ssh key sent by the client, nor the sshd logs, nor the tcpdump ascii dump.

Any idea to get this key ? I have no access to the client side.

The client never sends the full private key to the server, hence you can't dump it on the server. — Gerald Schneider, Jun 07 '22 at 13:32

score 1 · Accepted Answer · answered Jun 07 '22 at 14:12

1

Ask someone from the client side to share the public key, then check if it matches what you have on the server. The private key isn’t transmitted (and should be secure), so you can’t expect that.

answered Jun 07 '22 at 14:12

Ackack

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Dump client ssh key from server side

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