A Formally Verified Mechanism for Countering SPIT

Abstract

Abstract. Voice over IP (VoIP) is a key technology, which provides new ways of communication. It enables the transmission of telephone calls over the Internet, which delivers economical telephony that can clearly benefit both consumers and businesses, but it also provides a cheap method of mass advertising. Those bulks unsolicited calls are known as SPam over Internet Telephony (SPIT). In this paper we illustrate an anti-SPIT policy-based management (aSPM) mechanism which can handle the SPIT phenomenon. Moreover, we introduce a formal verification as a mean for validating the effectiveness of the aSPM against its intended goals. We provide model checking results that report upper bounds in the duration of call session establishment for the analyzed anti-SPIT policy over the Session Initiation Protocol (SIP) and prove the absence of deadlocks.

Detection and prevention of spam over Internet telephony in Voice over Internet Protocol networks using Markov chain with incremental SVM

“…Owing to the exponential growth of the spam calls, researchers have paved various ways for mitigating the SPIT calls using various techniques such as policy based, turing test based, reputation based, payment at risk, Completely Automated Public Turing test to tell the Computers and Humans Apart (CAPTCHA), machine learning algorithms based and content based over the period of 2006 to 2015 …”

“…However, these policy rules are insufficient to fight against SPIT calls, and an adequate knowledge is also required. Thus, the policy conditions are defined based on the in‐depth analysis of SPIT‐related threats and vulnerabilities that result to an action of either to block or notify or block with description using SIP message codes …”

The Sphinx enigma in critical VoIP infrastructures: Human or botnet?

“…Robustness properties that have been checked include (a) the absence of deadlocks and non-progress cycles (livelocks) in error-free communications, (b) fairness for the service users, (c) guaranteed call establishment for error-free SIP sessions, and (d) absence of message overload that could violate call establishment timeliness. All properties were formally verified by model checking a Sphinx system model developed in the SPIN toolset [13,14]. The model was parameterized based on measurements taken in our VoIP infrastructure, for the SIP message exchange times with (and without) the anti-SPIT policy.…”

Disabling a Computer by Exploiting Softphone Vulnerabilities: Threat and Mitigation

“…Kapravelos et al [9] presented a flow state based filter mechanism for preventing nuisance dialing but did not address false positive rates. Soupionis et al [22] detailed an audio based anti-bot verification method and more formal methods later [20,21]. In general, most existing VoIP defense mechanisms are designed to protect the VoIP servers, and be deployed close to them, rather than end hosts such as SIP softphones.…”