CAERUS: Chronoscopic Assessment Engine for Recovering Undocumented Specifications

A significant feature of embedded systems, in particular legacy systems, is their sensitivity to signal timing. Any modifications (e.g., security protections) to legacy systems could affect the timing of critical control signals. Some timing properties are well known (e.g., baud rates for communication). However, other timing properties are not well specified or understood. Those properties only surface as a result of additional testing such as part of modernization or upgrade efforts. We present a programmable hardware/software framework to recover and uncover the undocumented timing properties of embedded systems, CAERUS. CAERUS is based on commodity hardware components and the software has been open sourced.