DNS in Computer Forensics

The Domain Name Service (DNS) is a critical core component of the global Internet and integral to the majority of corporate intranets. It provides resolution services between the human-readable name-based system addresses and the machine operable Internet Protocol (IP) based addresses required for creating network level connections. Whilst structured as a globally dispersed resilient tree data structure, from the Global and Country Code Top Level Domains (gTLD/ccTLD) down to the individual site and system leaf nodes, it is highly resilient although vulnerable to various attacks, exploits and systematic failures. This paper examines the history along with the rapid growth of DNS up to its current critical status. It then explores the often overlooked value of DNS query data; from packet traces, DNS cache data, and DNS logs, with its use in System Forensics and more frequently in Network Forensics, extrapolating examples and experiments that enhance knowledge. Continuing on, it details the common attacks that can be used directly against the DNS systems and services, before following on with the malicious uses of DNS in direct system attacks, Distributed Denial of Service (DDoS), traditional Denial of Service (DOS) attacks and malware. It explores both cyber-criminal activities and cyber-warfare based attacks, and also extrapolates from a number of more recent attacks the possible methods for data exfiltration. It explores some of the potential analytical methodologies including; common uses in Intrusion Detection Systems (IDS), as well as infection and activity tracking in malware traffic analysis, and covers some of the associated methods around technology designed to defend against, mitigate, and/or manage these and other risks, plus the effect that ISP and nation states can have by direct manipulation of DNS queries and return traffic. This paper also investigates potential behavioural analysis and time-lining, which can then be used for the development of automated analysis methods during forensic investigations and as DNS is a network protocol, there is a predomination towards network based attacks and discovery. It shows the breadth of possible attacks and the scope of investigative approaches that can be employed. Overall it is an exploration of the area of DNS in Computer Forensics, additionally providing a foundation for educational exploration and further subject research: it concludes by bringing together all these aspects to support the Journal of Digital Forensics, Security and Law, Vol. 7(2) 12 importance of DNS analysis in Computer Forensics.