Edit the default Application Control profile

1. Go to Security Profiles > Application Control and edit the default profile.
2. In the Application Overrides section, click Add Signatures.

   

3. Click Add Filter and select Name.

   Enter Facebook to see a list of all signatures for Facebook applications.

   Click Select All and then click Use Selected Signatures.

   

4. In the Action column, check that all Facebook application signatures are set to Block.

   

5. Click Apply.