Millions of Facebook users access Facebook through their mobile phones. In case the hacker can gain access to the victims mobile phone then he can probably gain access to his/her Facebook account. Their are lots of Mobile Spying softwares used to monitor a Cellphone.
The most popular Mobile Phone Spying softwares are:
1. Mobile Spy
2. Spy Phone Gold
7. DNS Spoofing
If both the victim and attacker are on the same network, an attacker can use a DNS spoofing attack and change the original facebook.com page to his own fake page and hence can get access to victims facebook account.