Gentoo (jen-too) Penguins (Pygoscelis papua) are a species of brush-tailed penguin, recognizable by the patch of white feathering above their eyes. These marine birds can be found in parts of South America and Antarctica. Like other penguins, Gentoos are flightless birds, adapted instead for marine life. They are the fastest swimming penguins, able to reach speeds up to 22 mph.
Gentoo penguins live in large colonies on land, and take to the cold antarctic waters in search of food. They mainly feed on shrimp and krill, but sometimes hunt fish and even cephalopods. The ocean is a very dangerous place for them, however. Their main predators are leopard seals, sea lions, and killer whales.
Install Unattended Upgrades and enable the "unattended-upgrades" service.
Install ClamAV and enable "clamav-freshclam" service.
Install and run Lynis to audit your OS.
Use the "last -20" command to see the last 20 users that have been on the system.
Install UFW and enable the service.
Check your repo sources (eg; /etc/apt/).
Check the /etc/passwd and /etc/shadow lists for any unusual accounts.
User the finger command to check on activity summaries.
Check /var/logs for unusual activity.
Use "ps -aux | grep TERM" or "ps -ef | grep TERM" to check for suspicious ongoing processes.
Check for failed sudo attempts with "grep "NOT in sudoers" /var/log/auth.log.
Check journalctl for system messages.
Check to make sure rsyslog is running with "sudo systemctl status rsyslog" (or "sudo service rsyslog status") and if it's not enable with "sudo systemctl enable rsyslog".
Perform an nmap scan on your machine/network.
User netstat to check for unusual network activity.
Use various security apps to test you machine and network.
Change your config files for various services (ssh, apache2, etc) to non-standard configurations.
Disabled guest accounts.
Double up on ssh security by requiring both keys and passwords.
Check your package manager for any install suspicious apps (keyloggers, cleaners, etc).
The gentoo penguin is monogamous, and unfaithful penguins are often kicked out of the colony. Their species name comes from the naturalist who first discovered them mistakenly believing that they lived in Papua.