Software security: Vulnerabilities and countermeasures for two attacker models

History has shown that attacks against network-connected software based systems are common and dangerous. An important fraction of these attacks exploit implementation details of the software based system. These attacks - sometimes called low-level attacks - rely on characteristics of the hardware, compiler or operating system used to execute software programs to make these programs misbehave, or to extract sensitive information from them. With the increased Internet-connectivity of embedded devices, including industrial control systems, sensors as well as consumer devices, there is a substantial risk that similar attacks will target these devices. This tutorial paper explains the vulnerabilities, attacks and countermeasures relevant for low-level software security. The paper discusses software security for two different attacker models: the classic model of an attacker that can only interact with the program by providing input and reading output, and the more recent and challenging model of an attacker that controls part of the execution platform on which the software runs, for instance because the attacker has compromised the operating system, or some of the libraries that the software under attack relies on.