Secure Calls and Caller ID Spoofing Countermeasures Towards building a Cyber Smart Societies

Abstract

the point code of the originating switch will be used rather than the number of originator which means in reverse dialing mode, call will still be spoofed. While PSTN networks are “circuit switched” the IP traffic aims for the “shortest path”. This brings the infrastructure cost to a fraction of conventional telephony networks. Lower costs come with a a few downsides however. The advent of Session Initiation protocol (SIP) has reduced the network costs. The interactive voice response records are created on the fly at SIP application servers and SIP URIs are presented to the receiver exchanges which poses a challenging situation for SIP-SS7 gateways in call path. Hence delivering calls to the clients with vulnerable caller IDs. Among countless voice of IP clients, H.323 [2], and IAX2 [4] are widely used with their own security flaws [3] and adaptability issues. In mobile networks the IMSI/MEID is assigned a subscriber number that is used for sim card validation which intern fed to CNAM service. In some counties, the CNAM service is username based, in others its mainly an extension of IMSI number. In VoIP infrastructure, the SIP URI is presented but SIP B2BUA strips the URI and assigns it SIP proxy without verifying the information. The SIP proxy forwarding happens for every hop without client verification which discloses inherent weakness in the SIP standards. In this paper, we enumerate different methods of caller ID spoofing and perform a comparative analysis of these techniques. Based on our findings, we identify solution areas and we propose solutions that could be used in order to strength the Identification security in the telecommunication networks. We also present a domain name system based method that we plan to use as a building block for our caller ID spoofing solution. We propose that all IP-based traffic should be verified through SIP proxy and hence can be rejected or accepted based on the confidence shown on its routing patters. As we suggest service providers to tighten up the screws in their infrastructure, the DNS-based service that we are working on is entirely client-based and does not cost extra to the service provider. The rest of the paper is organised as follows: we first analyse the problem definition in both mobile, cellular and tradition PSTN networks. We also analyse the solutions of these problems proposed in academia in the related work section. We