The easiest way to slow and often prevent malware is to keep every system up to date. Fortunately, Linux (similar to Windows) has mechanisms that enable every system to be kept up to date. Reduce the spread of malware by keeping systems up to date, using complex passwords (at least 8 digits in length with uppercase letter, lowercase letters, symbols, and numbers), and never ever open an attachment that is not expected!
Tested on Raspberry Pi "Bullseye" (v11)
Log in to the PI
Open the terminal window (if logged in via the GUI instead of SSH)
Next, download the current package lists:
sudo apt update
After the package lists are updated, install the package:
sudo apt install unattended-upgrades
You may be prompted to enter "y" to install the package...
After the package is installed, perform a "dry run" to confirm it will work:
sudo unattended-upgrade -d -v --dry-run
This will cause it to verify package lists, check for updates, and it will get all the way to the point of installing them before it stops without making any changes
Now, enable it:
sudo dpkg-reconfigure --priority=low unattended-upgrades
When prompted, answer Yes to confirm the system should apply updates automatically