Network File Sharing Security

TL;DR

Yes, others on your network might be able to see your files if you have file sharing turned on. This guide shows you how to check and fix it.

Checking Your File Sharing Settings (Windows)

1. Open Network and Sharing Center: Right-click the network icon in your system tray (bottom right of screen) and select ‘Open Network & Internet settings’.
2. Advanced sharing settings: Click ‘Change advanced sharing settings’ on the left.
3. Turn off network discovery: Under ‘Private (current profile)’, make sure ‘Turn off network discovery’ is selected. This stops your computer from broadcasting its presence to others.
4. Disable file and printer sharing: Also under ‘Private (current profile)’, select ‘Turn off file and printer sharing’. This prevents others from seeing shared folders.
5. Password protected sharing: Under ‘All Networks’, it’s best to choose ‘Turn on password protected sharing’. This means anyone trying to access your files will need a username and password that exists on your computer.
6. Save changes: Click ‘Save changes’.

Checking Your File Sharing Settings (macOS)

1. Open System Preferences: Click the Apple menu in the top-left corner and select ‘System Preferences’.
2. Sharing: Click ‘Sharing’.
3. File Sharing: Select ‘File Sharing’ on the left.
4. Turn off File Sharing: Uncheck the box next to ‘File Sharing’ to completely disable it. If you want to keep sharing some files, carefully review which folders are shared and with whom.
5. Options…: Click ‘Options…’ to manage user access. Ensure only authorized users have read/write permissions.

Checking for SMBv1 (Windows – Advanced)

SMBv1 is an old file sharing protocol with known security vulnerabilities. It’s best to disable it.

1. Open Control Panel: Search for ‘Control Panel’ in the Start menu and open it.
2. Programs: Click ‘Programs’.
3. Turn Windows features on or off: Click ‘Turn Windows features on or off’.
4. SMB 1.0/CIFS File Sharing Support: Uncheck the box next to ‘SMB 1.0/CIFS File Sharing Support’ (you might see multiple options, uncheck them all).
5. Click OK: You may need to restart your computer for the changes to take effect.

Using a Firewall

A firewall acts as a barrier between your computer and the network. It can block unwanted access.

• Windows Firewall: Windows has a built-in firewall that’s usually enabled by default. You can check its status in ‘Control Panel > System and Security > Windows Defender Firewall’.
• macOS Firewall: macOS also has a firewall (‘System Preferences > Security & Privacy > Firewall’). Make sure it’s turned on, and review the application-specific rules to ensure only trusted applications can accept incoming connections.

Public Networks

Important: When connected to a public Wi-Fi network (e.g., in a coffee shop), always disable file sharing completely and enable your firewall. Public networks are less secure.

Checking Network Connections (Advanced)

You can use command line tools to see active network connections, which might reveal unexpected file sharing activity.

• Windows: Open Command Prompt as administrator and run

  net share

  . This lists shared folders on your computer.

• macOS: Open Terminal and run

  smbutil status

  . This shows SMB connections.