Gsm was cracked last decade. Now the Telecom came up with new NGN, LTE with better capacity and capability. But at the same time it comes up with critical vulnerabilities too. It could be exploited and cause serious risks to voice as well as data privacy. The all IP-Based network has brought internet risk into it giving chance to attacks like DDOS, MITM, SIP Session Hijacking, Botnets to be used by the intruders. The new protocols like SCTP, SCCP uses point codes and GT to communicate between infrastructure elements like MME, IMS, STP, HSS that could be exploited to find out entry point into the Telecom so far called closed networks. Difference between SS7 attack vectors and SIGTRAN attack vectors along with along with the application layer attacks will be discussed here.