Detection of Algorithmicallygenerated Malicious Domain Using Frequency Analysis

Malicious use and exploitation of Dynamic Domain Name Services (DDNS) capabilities poses a serious threat to the information security of organisations and businesses. In recent times, many malware writers have relied on DDNS to maintain their Command and Control (C&C) network infrastructure to ensure a persistence presence on a compromised host. Amongst the various DDNS techniques, Domain Generation Algorithm (DGA) is often perceived as the most elusive and difficult to detect using traditional methods. This paper presents an approach for detecting DGA using frequency analysis of the character distribution and the weighted scores of the domain names. The approach’s feasibility is demonstrated using a range of legitimate domains and a number of malicious algorithmically-generated domain names. When a weighted score of < 45 is applied to the Alexa one million list of domain names, only 15% of the domain names were treated as non-human generated.