Chaos Communication Congress

Do as I Say not as I Do: Stealth Modification of Programmable Logic Controllers I/O by Pin Control Attack (33x100)

Data di messa in onda: Dic 29, 2016

Speakers: Ali Abbasi, Majid Input/Output is the mechanisms through which embedded systems interact and control the outside world. Particularly when employed in mission critical systems, the I/O of embedded systems has to be both reliable and secure. Embedded system’s I/O is controlled by a pin based approach. In this work, we investigate the security implications of embedded system’s pin control. In particular, we show how an attacker can tamper with the integrity and availability of an embedded system’s I/O by exploiting cerain pin control operations and the lack of hardware interrupts associated to them. Embedded systems are widely used today in a variety of applications, such as consumer, industrial, automotive, medical, commercial and military. As such, they are often employed in mission critical systems that have to be both reliable and secure. In particular, it is important that their I/O (Input/Output) be stable and secure, as this is the way they interact with the outside world. Digging into their architecture, we know that the I/O interfaces of embedded systems (e.g., GPIO, SCI, USB, etc.), are usually controlled by a so-called System on a Chip (SoC), an integrated circuit that combines multiple I/O interfaces. In turn, the pins in a SoC are managed by a pin controller, a subsystem of SoC, through which one can configure pin multiplexing or the input or output mode of pins. One of the most peculiar aspects of a pin controller is that its behavior is determined by a set of registers: by altering these registers one can change the behavior of the chip in a dramatic way. This feature is exploitable by attackers, who can tamper with the integrity or the availability of legitimate I/O operations, factually changing how an embedded system interacts with the outside world. Based on these observations, in this research, we introduce a novel attack technique against embedded systems, which we call pin control attack. As we will demonstrate in the work,