A paging request triggered by a Facebook message can allow an attacker to link your temporary identifier to your Facebook identity and track your movements," explains Asokan." Paging is the process of locating the user in a particular area. If you also have a Facebook Messenger application installed in your 4G device, these messages in the “Other” mailbox cause a paging request by the network. The user will not be notified upon the reception of the message. "If you receive messages from people that are not in your friend list in Facebook, these messages end up in the “Other” mail box. But social network messaging applications, such as Facebook Messenger and WhatsApp, can still be used to trigger signaling messages that leak information to the attacker. Temporary identifiers are random and updated frequently, in order to prevent an attacker to link a temporary identifier to the permanent identifier or track movements of a given user. When a mobile device attaches to a network, it is given a temporary identifier. They are even low cost, anyone can purchase the equipment for a little over one thousand euros. The necessary equipment for all forms of attacks is inexpensive and readily available. The target user can be localized within a 2 km2 area in an urban setting. Location leak of the mobile phone may include forcing the 4G device into revealing its location. "We built a 4G fake base station and showed that most popular phones can be tricked into giving up location information or degrading their service level, states Professor N. 4G was thought to provide strong privacy and availability guarantees for mobile users, assuming that for instance tracking the user movement would be impossible or ineffective."