Lesson 5.2: Patching and updates
Most successful attacks use vulnerabilities that already have a fix. How a Linux server gets security updates, why installing them isn't the end (services and the kernel keep running old code until restarted), and how to make updates automatic so they don't depend on someone remembering. In the lab you refresh the package lists, see pending security updates for sudo, OpenSSH and OpenSSL, install them, restart SSH, find out that a reboot is waiting for a new kernel, and switch on unattended upgrades.
16 min
You will learn to
- Explain why patching is the most effective control
- List and install pending updates with apt
- Restart services after updates
- Recognise a pending reboot
- Enable unattended security upgrades
Key terms
- Patch
- An update that fixes a bug or vulnerability.
- Unattended upgrades
- Ubuntu/Debian's service that installs security updates automatically.
- Restart after patching
- Running processes keep the old code in memory until they restart; the kernel until the machine reboots.
- Maintenance window
- An agreed time when changes and reboots may happen.
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