Code-reuse attacks, including return-oriented programming (ROP) and jump-oriented programming, bypass defenses against code injection by repurposing existing executable code in application binaries and shared libraries toward a malicious end. A common feature of these attacks is the reliance on the knowledge of the layout of the executable code. We propose a fine grained randomization based approach that modifies the layout of executable code and hinders code-reuse attack. Our solution consists solely of a modified dynamic loader that randomizes the internal structure of the executable code, thereby denying the attacker the necessary apriori knowledge for constructing the desired sequence of gadgets. Our approach has the advantage that it can be applied to any ELF binary and every execution of this binary uses a different randomization. We describe the initial implementation of Marlin, a customized loader for randomization of executable code. Our work shows that such an approach is feasible and significantly increases the level of security against code-reuse attacks.

Cryptographers have proposed the notion of read-once keys (ROKs) as a beneficial tool for a number of applications, such as delegation of authority. The premise of ROKs is that the key is destroyed by the process of reading it, thus preventing subsequent accesses. While the idea and the applications are well-understood, the consensus among cryptographers is that ROKs cannot be produced by algorithmic processes alone. Rather, a trusted hardware mechanism is needed to support the destruction of the key. In this work, we propose one such approach for using a hardware design to generate ROKs. Our approach is an application of physically unclonable functions (PUFs). PUFs use the intrinsic differences in hardware behavior to produce a random function that is unique to that hardware instance. Our design consists of incorporating the PUF in a feedback loop to make reading the key multiple times physically impossible.

In a distributed computing environment, remote devices must often be granted access to sensitive information. In such settings, it is desirable to restrict access only to known, trusted devices. While approaches based on public key infrastructure and trusted hardware can be used in many cases, there are settings for which these solutions are not practical. In this work, we define physically restricted access control to reflect the practice of binding access to devices based on their intrinsic properties. Our approach is based on the application of physically unclonable functions. We define and formally analyze protocols enforcing this policy, and present experimental results observed from developing a prototype implementation. Our results show that non-deterministic physical properties of devices can be used as a reliable authentication and access control factor.