Determining the Causes of AccuVote Optical Scan Voting Terminal Memory Card Failures

Posted: August 13th, 2010 | Author: | Filed under: Other Publications | Tags: , , , , , , ,

Determining the Causes of AccuVote Optical Scan Voting Terminal Memory Card Failures
Tigran Antonyan, Nicolas Nicolaou Alexander Shvartsman and Therese Smith
In Proceedings of the 2010 USENIX/ACCURATE Electronic Voting Workshop (EVT 10)
August 11–13, 2010, Washington, DC, USA www.usenix.org/events/evtwote10/

Abstract
Optical scan (OS) voting systems play an increasing role in the United States elections, with over 40 states deploying such systems. The AccuVote optical scanners (AV-OS) manufactured by ES&S account for over 20% of all OS systems. OS systems typically use removable media (cards) to provide election-specific programming to the scanners and to convey precinct election results for central tabulation. Several reports document occurrences of AV-OS memory card failures, with up to 15% of all cards failing in some cases.

This paper reports on determining the causes of memory card failures that lead to complete loss of data from the card. An initial experimental analysis identified the battery discharge as a significant part of the problem. This finding led to the question of the dependability of the builtin function of the AccuVote OS system that issues a warning when the memory card contains a low-voltage battery. We identified the components used to implement this function in one type of AccuVote memory card. Using the specifications of the commodity batteries that are used in these cards, we determined the time interval from the instant when a battery warning is issued by the AccuVote to the point when the battery does not have enough voltage to retain data on the memory card. We show that such interval is about 2 weeks. Thus timely warnings cannot be provided to protect against battery discharge and loss of data during the election process. The factors contributing to the short warning interval are likely to apply to other battery-backed RAM cards, such as those used in the ES&S Model 100. Recommendations for mitigating the problem are made in light of the expected behavior of the warning system.

Research funded by the Secretary of the State of Connecticut and performed at the Center for Voting Technology Research at the University of Connecticut.

Full Paper: evt2010


Tampering with Special Purpose Trusted Computing Devices: A Case Study in Optical Scan E-Voting

Posted: December 10th, 2007 | Author: | Filed under: Other Publications | Tags: , , , , , ,

Tampering with Special Purpose Trusted Computing Devices: A Case Study in Optical Scan E-Voting
Aggelos Kiayias, Laurent Michel, Alexander Russell, Narasimha Shashidhar, Andrew See, Alexander Shvartsman and Seda Davtyan
In Proceedings of the Twenty-Third Annual Computer Security Applications Conference (ACSAC 2007)
December 10-14, 2007, Miami, Florida www.acsac.org/

Abstract
Special purpose trusted computing devices are currently being deployed to offer many services for which the general purpose computing paradigm is unsuitable. The nature of the services offered by many of these devices demand high security and reliability, as well as low cost and low power consumption. Electronic Voting machines is a canonical example of this phenomenon. With electronic voting machines currently being used in much of the United States and several other countries, there is a strong need for thorough security evaluation of these devices and the procedures in place for their use. In this work, we first put forth a general framework for special purpose trusted computing devices. We then focus on Optical Scan (OS) electronic voting technology as a specific instance of this framework. OS terminals are a popular e-voting technology with the decided advantage of a user-verified paper trail: the ballot sheets themselves. Still election results are based on machine generated totals as well as machine-generated audit reports to validate the voting process.

In this paper we present a security assessment of the Diebold AccuVote Optical Scan voting terminal (AV-OS), a popular OS terminal currently in wide deployment anticipating the 2008 Presidential elections. The assessment is developed using exclusively reverse-engineering, without any technical specifications provided by the machine suppliers. We demonstrate a number of security issues that relate to the machine’s proprietary language, called AccuBasic, that is used for reporting election results. While this language is thought to be benign, especially given that it is essentially sandboxed by the firmware to have only read access, we demonstrate that it is powerful enough to (i) strengthen known attacks against the AV-OS so that they become undetectable prior to elections (and thus significantly increasing their magnitude) or, (ii) to conditionally bias the election results to reach a desired outcome. Given the discovered vulnerabilities and attacks we proceed to discuss how random audits can be used to validate with high confidence that a procedure carried out by special purpose devices such as the AV-OS has not been manipulated. We end with a set of recommendations for the design and safe-use of OS voting systems.

Download full paper:: acsac07-voter.pdf


A Summary Comparison of the Optical Scan (OS) and the Touch Screen (TS) Voting Terminals

Posted: June 29th, 2007 | Author: | Filed under: Other Publications | Tags: , , , , , ,

This summary presents an impartial discussion of the two voting technologies in wide use as of this writing (2007): Optical Scan and Touch Screen technologies. The purpose of the presentation is to better the understanding of the pros and cons offered by these two technologies.

Technical reports:


vc-os-ts.pdf
vc-os-ts.doc


Security Assessment of the Diebold Optical Scan Voting Terminal

Posted: October 30th, 2006 | Author: | Filed under: Other Publications | Tags: , , , , , ,

We present an independent security evaluation of the AccuVote Optical Scan voting terminal (AV-OS). We identify a number of new vulnerabilities of this system which, if exploited maliciously, can invalidate the results of an election process utilizing the terminal. Furthermore, based on our findings an AV-OS can be compromised with off-the-shelf equipment in a matter of minutes even if the machine has its removable memory card sealed in place. The basic attack can be applied to effect a variety of results, including entirely neutralizing one candidate so that their votes are not counted, swapping the votes of two candidates, or biasing the results by shifting some votes from one candidate to another. Such vote tabulation corruptions can lay dormant until the election day, thus avoiding detection through pre-election tests.

Based on these findings, we describe new safe-use recommendations for the AV-OS terminal. Specifically, we recommend installation of tamper-resistant seals for (i) removable memory cards, (ii) serial port, (iii) telephone jacks, as well as (iv) screws that allow access into the terminal’s interior; failure to seal any single one of these components renders the terminal susceptible to the attack outlined above. An alternative is to seal the entire Optical Scan system (sans ballot box) into a tamper-resistant container at all times other than preparation for election and deployment in an election. An unbroken chain of custody must be enforced at all times. Post-election audits are also strongly advised.
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