If you need to view a private profile, the safest and only supported methods involve standard social networking practices:

Review and remove recently used third-party apps that have access to your Facebook data. Facebook·2600 - The Hacker Quarterly

: Many profile "trackers" collect your device info and app activity, often sharing it with third parties for advertising or more nefarious purposes. Legitimate Ways to Interact with Private Profiles

: You may be able to see shared content if you have mutual connections who are tagged in the person's posts. How to Protect Your Own Profile

: Some sites use fake login pages to trick you into entering your own email and password, giving hackers full access to your account.