Extending Black Domain Name List by Using Co-occurrence Relation between DNS Queries

Abstract

Botnet threats, such as server attacks or sending of spam e-mail, have been increasing. Therefore, infected hosts must be found and their malicious activities mitigated. An effective method for finding infected hosts is to use a blacklist of domain names. When a bot receives attack commands from a Command and Control (CC therefore a blacklist cannot cover all black domain names. We thus present a method for finding unknown black domain names by using DNS query data and an existing blacklist of known black domain names. To achieve this, we focus on DNS queries sent by infected hosts. One bot sends several queries on black domain names due to C&C server redundancy. We use the co-occurrence relation of two different domain names to find unknown black domain names and extend the blacklist. If a domain name frequently co-occurs with a known black name, we assume that the domain name is also black. A cross-validation evaluation of the proposed method showed that 91.2% of domain names that are on the validation list scored in the top 1%.