in it's
redacted version at the links below. :)
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Black Box Voting : Latest Consumer Reports from Black Box Voting: 5-11-06: Three-level security flaws found in Diebold touch-screens
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Posted by Bev Harris on Thursday, May 11, 2006 - 12:34 pm:
Due to the nature of this report it is distributed in two different
versions. Details of the attack are only in the restricted
distribution version considered to be confidential. Fewer than 50
words have been redacted in the version below.
Overview
http://www.blackboxvoting.org/BBVtsxstudy.pdf 327 KB
Critical Security Alert: Diebold TSx and TS6 voting systems
by Harri Hursti
for Black Box Voting, Inc.Note: Please refrain from speculation or public discussion of
inappropriate technical details.This document describes several security issues with the Diebold
electronic voting terminals TSx and TS6. These touch-pad terminals are
widely used in US and Canadian elections and are among the most widely
used touch pad voting systems in North America. Several
vulnerabilities are described in this report.
One of them, however, seems to enable a malicious person to compromise
the equipment even years before actually using the exploit, possibly
leaving the voting terminal incurably compromised.
These architectural defects are not in the election-processing system
itself. However, they compromise the underlying platform and therefore
cast a serious question over the integrity of the vote. These exploits
can be used to affect the trustworthiness of the system or to
selectively disenfranchise groups of voters through denial of service.
Three-layer architecture, 3 security problems
Each can stand alone or combine for 3-layer offense in depth
As an oversimplification, the systems in question have three major
software layers: boot loader, operating system and application
program. As appropriate for current designs, the first two layers
should contain all hardware specific implementations and
modifications, while the application layer should access the hardware
– the touch pad, memory card, the network etc. – only via services and
functions provided by the operating system and therefore be
independent of the hardware design. Whether the architecture in
question follows these basic guidelines is unknown.
Based on publicly available documentation, source code excerpts and
testing performed with the system, there seem to be several backdoors
to the system which are unacceptable from a security point of view.
These backdoors exist in each of these three layers and they allow the
system to be modified in extremely flexible ways without even basic
levels of security involved.
In the worst case scenario, the architectural weaknesses incorporated
in these voting terminals allow a sophisticated attacker to develop an
"offense in depth" approach in which each compromised layer will also
become the guardian against clean-up efforts in the other layers. This
kind of deep attack is extremely persistent and it is noteworthy that
the layers can conceal the contamination very effectively should the
attacker wish that. A quite natural strategy in these types of
situations is to penetrate, modify and make everything look normal.
Well documented viral attacks exist in similar systems deploying
interception and falsification of hash-code calculations used to
verify integrity in the higher application levels to avoid detection.
The three-level attack is the worst possible attack. However, each
layer can also be used to deploy a stand-alone attack. The TSx systems
examined appear to offer opportunities for the three-level attack as
well as the stand-alone attacks.
It is important to understand that these attacks are permanent in
nature, surviving through the election cycles. Therefore, the
contamination can happen at any point of the device's life cycle and
remain active and undetected from the point of contamination on
through multiple election cycles and even software upgrade cycles.
Here is a rough analogy:
- The application can be imagined as written instructions on a paper.
If it is possible to replace these instructions, as it indeed seems,
then the attacker can do whatever he wishes as long as the
instructions are used.
- The operating system is the man reading the instructions. If he can
be brainwashed according to the wishes of the attacker, then even
correct instructions on the paper solve nothing. The man can decide to
selectively do something different than the instructions. New paper
instructions come and go, and the attacker can decide which
instructions to follow because the operating system itself is under
his control.
- The boot loader is the supreme entity that creates the man, the
world and everything in it. In addition to creating, the boot loader
also defines what is allowed in the world and delegates part of that
responsibility to the operating system. If the attacker can replace
the boot loader, trying to change the paper instructions or the man
reading them does not work. The supreme entity will always have the
power to replace the man with his own favorite, or perhaps he just
modifies the man’s eyes and ears: Every time the man sees yellow, the
supreme being makes him think he is seeing brown. The supreme entity
can give the man two heads and a secret magic word to trigger
switching the heads.
In the world of the Diebold touch-screen voting terminals, all of
these attacks look possible.
The instructions (applications and files) can be changed. The man
reading the files (Windows CE Operating System and the libraries) can
be changed. Or the supreme entity (boot loader) can be changed, giving
total control over the operating system and the files even if they are
"clean software."
Specific conceptual information is contained in the report, with
details and filenames in the high-security version which is being
delivered under cryptographic and/or personal signature controls to
the EAC, Diebold CEO Tom Swidarski and CERT.
1) Boot loader reflashing
2) Operating system reflashing
3) Selective file replacement
In addition, the casing of the TSx machines lack basic seals and
security, and within the casing additional exploitations are found.
Conclusions and Recommendations
Because there is no way of having chain of custody or audit trail for
machines, the machines need to be reflashed with a known good version
(assessing the risks potentially inherited). Ideally this should be
done by the proper governmental authorities rather than being
outsourced.
After that, extensive chain of custody management has to be
established to make sure that machines do not potentially get
recontaminated. Less than five minutes is required for contamination.
The bootloader needs to be re-engineered.
The cases need to be properly and permanently sealed.
Further study is warranted around these issues and others in the May
15, 2006 Supplemental Report for the Emery County TSx study.
While these flaws in design are not in the vote-processing system
itself, they potentially seriously compromise election security. It
would be helpful to learn how existing oversight processes have failed
to identify this threat.
A secondary report will be released on May 15, 2006. This report
contains approximately 12 other areas of secondary concern to the
problems described in this initial report.
PERMISSION TO REPRINT GRANTED, WITH LINK TO
http://www.blackboxvoting.org------------------------------------------------------------
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http://www.bbvforums.org/cgi-bin/forums/show.cgi?1954/27675
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