🛠️ Day 8: Linux Services

Services are the silent workers of your operating system. 👷‍♂️

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🆚 Service vs. Process

A Service is essentially a process that runs in the background, often starting automatically at boot.

Feature	Service 🛠️	Process 🏃
Start	Automatic or Manual	Manual (User)
Mode	Background (Daemon)	Foreground (mostly)
Lifespan	Long-running	Often short-lived
Example	ssh, apache2	ls, cd, cat

Note: In Kali, systemd is the manager that controls these services.

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🕹️ Essential Service Commands

Manage your services using systemctl.

1. Check Status

systemctl status ssh

Look for Active: active (running) to confirm it's working.

2. Start a Service

sudo systemctl start ssh

Starts the service immediately.

3. Stop a Service

sudo systemctl stop ssh

Stops the service immediately.

4. Enable at Boot

sudo systemctl enable ssh

Ensures the service starts automatically when you turn on the computer.

5. Disable at Boot

sudo systemctl disable ssh

Prevents the service from starting automatically.

6. Restart

sudo systemctl restart ssh

Stops and then starts the service (useful for applying config changes).

7. List Running Services

systemctl --type=service --state=running

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⚠️ Why Services Matter?

Understanding services is critical for security:

• Target: Hackers often target services rather than simple processes.
• Persistence: Malware often installs itself as a service to run continuously in the background using misleading names to hide.
• Privilege: If a vulnerable service runs as root, compromising it gives the attacker full control. 👻

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