A Detour Strategy for Visiting Phishing URLs Based on Dynamic DNS Response Policy Zone

Abstract

Email based Uniform Resource Locator (URL) distribution is one of the popular ways for starting phishing attacks. Conventional anti-phishing solutions rely on security facilities and investigate all incoming emails. This makes the security facilities get overloaded and cause consequences of upgrades or new deployments even with no better options. This paper presents a novel detour strategy for the traffic of visiting potential phishing URLs based on dynamic Domain Name System (DNS) Response Policy Zone (RPZ) in order to mitigate the overloads on security facilities. In the strategy, the URLs included in the incoming emails will be extracted and the corresponding Fully Qualified Domain Name (FQDN) will be registered in the RPZ of the local DNS cache server with mapping the IP address of a special Hypertext Transfer Protocol (HTTP) proxy. The contribution of the approach is to avoid heavy investigations on all incoming emails and mitigate the overloads on security facilities by directing the traffic to phishing URLs to the special HTTP proxy connected with a set of security facilities conducting various inspections. The evaluation results on the prototype system showed that the URL extraction and FQDN registration were finished before the emails had been delivered and accesses to the URLs were successfully directed to the special HTTP proxy. The results of overhead measurements also confirmed that the proposed strategy only affected the internal email server with 11% of performance decrease on the prototype system.