Packet header attack by hardware trojan in NoC based TCMP and its impact analysis

With the advancement of VLSI technology, Tiled Chip Multicore Processors (TCMP) with packet switched Network-on-Chip (NoC) have been emerged as the backbone of the modern data intensive parallel systems. Due to tight time-to-market constraints, manufacturers are exploring the possibility of integrating several third-party Intellectual Property (IP) cores in their TCMP designs. Presence of malicious Hardware Trojan (HT) in the NoC routers can adversely affect communication between tiles leading to degradation of overall system performance. In this paper, we model an HT mounted on the input buffers of NoC routers that can alter the destination address field of selected NoC packets. We study the impact of such HTs and analyse its first and second order impacts at the core level, cache level, and NoC level both quantitatively and qualitatively. Our experimental study shows that the proposed HT can bring application to a complete halt by stalling instruction issue and can significantly impact the miss penalty of L1 caches. The impact of re-transmission techniques in the context of HT impacted packets getting discarded is also studied. We also expose the unrealistic assumptions and unacceptable latency overheads of existing mitigation techniques for packet header attacks and emphasise the need for alternative cost effective HT management techniques for the same.