Difference between revisions of "Sshd"

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CMD ["/usr/sbin/sshd", "-D"]
 
CMD ["/usr/sbin/sshd", "-D"]
  
 +
```
 +
 +
Nonroot
 +
 +
```
 +
#!/bin/bash
 +
set -eux
 +
mkdir -p ${HOME}/custom_ssh
 +
ssh-keygen -f ${HOME}/custom_ssh/ssh_host_rsa_key -N '' -t rsa
 +
ssh-keygen -f ${HOME}/custom_ssh/ssh_host_dsa_key -N '' -t dsa
 +
 +
cat << EOF > ${HOME}/custom_ssh/sshd_config
 +
Port 2222
 +
HostKey ${HOME}/custom_ssh/ssh_host_rsa_key
 +
HostKey ${HOME}/custom_ssh/ssh_host_dsa_key
 +
AuthorizedKeysFile  .ssh/authorized_keys
 +
ChallengeResponseAuthentication no
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UsePAM yes
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Subsystem  sftp    /usr/lib/ssh/sftp-server
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PidFile ${HOME}/custom_ssh/sshd.pid
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EOF
 +
 +
/usr/local/bin/sshd -f ${HOME}/custom_ssh/sshd_config
 +
echo "----- Process ID : ${HOME}/custom_ssh/sshd.pid -------"
 
```
 
```

Latest revision as of 06:12, 21 October 2023

Secure with specific ciphers

~]$ sudo sshd -T | grep ^macs
macs umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512
~]$ sudo sshd -T | grep ^kexa
kexalgorithms curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512

/etc/ssh/sshd_config

kexalgorithms curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512
macs umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512
sudo systemctl restart sshd

Check via ssh scan

https://sshcheck.com/

which is probably this parsed and prettied

sudo nmap -sV --script ssh2-enum-algos ssh.example.org -p 22

Dockerfile run in foreground

EXPOSE 22
CMD ["/usr/sbin/sshd", "-D"]

Nonroot

#!/bin/bash
set -eux
mkdir -p ${HOME}/custom_ssh
ssh-keygen -f ${HOME}/custom_ssh/ssh_host_rsa_key -N '' -t rsa
ssh-keygen -f ${HOME}/custom_ssh/ssh_host_dsa_key -N '' -t dsa

cat << EOF > ${HOME}/custom_ssh/sshd_config
Port 2222
HostKey ${HOME}/custom_ssh/ssh_host_rsa_key
HostKey ${HOME}/custom_ssh/ssh_host_dsa_key
AuthorizedKeysFile  .ssh/authorized_keys
ChallengeResponseAuthentication no
UsePAM yes
Subsystem   sftp    /usr/lib/ssh/sftp-server
PidFile ${HOME}/custom_ssh/sshd.pid
EOF

/usr/local/bin/sshd -f ${HOME}/custom_ssh/sshd_config
echo "----- Process ID : ${HOME}/custom_ssh/sshd.pid -------"