Interrupt-oriented Bugdoor Programming: A Minimalist Approach to Bugdooring Embedded Systems Firmware

Tan, S.J., Bratus, S., Goodspeed, T

2014 Annual Computer Security Applications Conference, December 2014.

Visit Publisher Online Entry:

We demonstrate a simple set of interrupt-related vulnerability primitives that, despite being apparently innocuous, give attackers full control of a microcontroller platform. We then present a novel, minimalist approach to constructing deniable bugdoors for microcontroller firmware, and contrast this approach with the current focus of exploitation research on demonstrations of maximum computational power that malicious computation can achieve. Since the introduction of Return-oriented programming, an ever-increasing number of targets have been demonstrated to unintentionally yield Turing-complete computation environments to attackers controlling the target's various input channels, under ever more restrictive sets of limitations. Yet although modern OS defensive measures indeed require complex computations to bypass, this focus on maximum expressiveness of exploit programming models leads researchers to overlook other research directions for platforms that lack strong defensive measure but occur in mission-critical systems, namely, microcontrollers. In these systems, common exploiter goals such as sensitive code and data exfiltration or arbitrary code execution do not typically require complex computation; instead, a minimal computation is preferred and a simple set of vulnerability primitives typically suffices. We discuss examples of vulnerabilities and the new kinds of tools needed to avoid them in future firmware.

Publication Status:
Publication Type:
Publication Date:
Copyright Notice:

This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.

  1. The following copyright notice applies to all of the above items that appear in IEEE publications: "Personal use of this material is permitted. However, permission to reprint/publish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from IEEE."

  2. The following copyright notice applies to all of the above items that appear in ACM publications: "© ACM, effective the year of publication shown in the bibliographic information. This file is the author’s version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in the journal or proceedings indicated in the bibliographic data for each item."

  3. The following copyright notice applies to all of the above items that appear in IFAC publications: "Document is being reproduced under permission of the Copyright Holder. Use or reproduction of the Document is for informational or personal use only."