Evaluating mail-based security for electoral processes using attack trees

Since the reports of Russian interference in the 2016 United States General Election, the security of voting processes has received increased attention from both state and federal authorities. The declaration by the US Department of Homeland Security in January 2017 that election systems be classified as the 17th component of critical infrastructure is just the beginning of a need for more secure voting processes. More recently, the COVID-19 pandemic and the 2020 US General Election have placed greater emphasis specifically on mail-based voting processes for electoral systems. The objective of this research is to provide greater insight into potential threats to mail-based voting processes. Upon identifying an attack tree as an initial structure for evaluation, new threats are postulated, and an updated tree is proposed that accounts for more recent activities. Then, using an established assessment framework, the relative likelihood of each mail-based voting process attack scenario is identified. The results facilitate providing election officials and policymakers with greater knowledge of how mail-based voting system vulnerabilities develop as well as specific security measures that may be most beneficial.