config/ssh/ssh_config

   1 # OpenSSH client configuration
   2 #
   3 # set some basic hardening options for all connections
   4 Host *
   5         # disable Roaming as it is known to be vulnerable
   6         UseRoaming no
   7
   8         # only use secure crypto algorithm
   9         KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
  10         Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
  11         MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com
  12
  13         # always visualise server host keys (has no technical
  14         # effect, but helps to identify key based MITM attacks)
  15         VisualHostKey yes
  16
  17         # use SSHFP (might work on some up-to-date networks) to look up host keys
  18         VerifyHostKeyDNS yes
  19
  20         # send keep-alive messages to connected server to avoid broken connections
  21         ServerAliveInterval 10
  22         ServerAliveCountMax 6
  23
  24         # disable X11 forwarding (security risk)
  25         ForwardX11 no
  26
  27         # always check server IP address
  28         CheckHostIP yes
  29
  30         # ensure only allowed authentication methods are used
  31         PreferredAuthentications publickey,keyboard-interactive,password
  32
  33 # EOF