Public bug reported: xenial @ 1:7.2p2-4ubuntu2.1 on amd64 has this bug. trusty @ 1:6.6p1-2ubuntu2.8 on amd64 does not have this bug. I have not tested any other ssh versions.
The following should reproduce the issue: #ssh-keyscan XXXX > ~/.ssh/known_hosts # ssh root@XXXXX Permission denied (publickey). # ssh-keygen -H /root/.ssh/known_hosts updated. Original contents retained as /root/.ssh/known_hosts.old WARNING: /root/.ssh/known_hosts.old contains unhashed entries Delete this file to ensure privacy of hostnames # ssh root@XXXXXX Permission denied (publickey). # ssh-keygen -H /root/.ssh/known_hosts updated. Original contents retained as /root/.ssh/known_hosts.old WARNING: /root/.ssh/known_hosts.old contains unhashed entries Delete this file to ensure privacy of hostnames # ssh root@XXXXX The authenticity of host 'XXXXXX' can't be established. RSA key fingerprint is XXXXXX. Are you sure you want to continue connecting (yes/no)? # diff known_hosts.old known_hosts 1c1 < |1|BoAbRpUE3F5AzyprJcbjdepeDh8=|x/1AcaLxh45FlShmVQnlgx2qjxY= XXXXX --- > |1|nTPsoLxCugQyZi3pqOa2pc/cX64=|bUH5qwZlZPp8msMGHdLtslf3Huk= XXXXX ** Affects: openssh (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1668093 Title: ssh-keygen -H corrupts already hashed entries To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/1668093/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs