A Comprehensive Analysis on Vulnerability of Active Shields to Tilted Microprobing Attacks
Qihang Shi, Huanyu Wang, Navid Asadizanjani, Mark Mohammad Tehranipoor, Domenic J. Forte · 2018
Microprobing attacks against integrated circuits used in security-critical systems have become a serious concern. With the help of advanced circuit editing technology, an attacker can remove layers of materials and expose wires carrying security critical information for probing. Active shields constitute the most widely used approach to deter microprobing attacks. However, a number of vulnerabilities have been found in existing active shield designs; in particular, their weakness to tilted bypass attacks has yet to be addressed. In this paper, we provide a comprehensive investigation on tilted bypass attacks with a mathematical model to investigate how best an attacker can exploit geometric weakness of shield designs in three dimensions, as well as shield design techniques informed with such observations. We also include a numerical analysis with realistic parameters to validate theoretical predictions.