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Archives for 2008

Unattended Voting Machines, As Usual

February 5, 2008 by

It’s election day, so tradition dictates that I publish some photos of myself with unattended voting machines.

To recap: It’s well known that paperless electronic voting machines are vulnerable to tampering, if an attacker can get physical access to a machine before the election. Most of the vendors, and a few election officials, claim that this isn’t a problem because the machines are well guarded so that no would-be attacker can get to them. Which would be mildly reassuring – if it were true.

Here’s me with two unattended voting machines, taken on Sunday evening in a Princeton polling place:

Here are four more unattended voting machines, taken on Monday evening in another Princeton polling place.

I stood conspicuously next to this second set of machines for fifteen minutes, and saw nobody.

In both cases I had ample opportunity to tamper with the machines – but of course I did not.

Filed Under: Other Topics, Privacy & Security Tagged With: , ,

Internet Voting

February 4, 2008 by

(or, how I learned to stop worrying and love having the whole world know exactly how I voted)

Tomorrow is “Super Tuesday” in the United States. Roughly half of the delegates to the Democratic and Republican conventions will be decided tomorrow, and the votes will be cast either in a polling place or through the mail. Except for the votes cast online. Yes, over the Internet.

The Libertarian Party of Arizona is conducting its entire primary election online. Arizona’s Libertarian voters who wish to participate in its primary election have no choice but to vote online. Also, the Democratic Party is experimenting with online voting for overseas voters.

Abridged history: The U.S. military has been pushing hard on getting something like this in place, most famously commissioning a system called “SERVE”. To their credit, they hired several smart security people to evaluate their security. Four of those experts published an independent report that was strongly critical of the system, notably pointing out the obvious problem with such a scheme: home computers are notoriously insecure. It’s easy to imagine viruses and whatnot being engineered to specifically watch for attempts to use the computer to vote and to specifically tamper with those votes, transparently shifting votes in the election. The military killed the program, later replacing it with a vote-by-fax scheme. It’s unclear whether this represents a security improvement, but it probably makes it easier to deal with the diversity of ballot styles.

Internet voting has also been used in a variety of other places, including Estonia. An Estonian colleague of mine demonstrated the system for me. He inserted his national ID card (a smartcard) into a PCMCIA card reader in his laptop. This allowed him to authenticate to an official government web site where he could then cast his vote. He was perfectly comfortable letting me watch the whole process because he said that he could go back and cast his vote again later, in private, overriding the vote that I saw him cast. This scheme partly addresses the risk of voter coercion and bribery (see sidebar), but it doesn’t do anything for the insecurity of the client platform.

Okay, then, how does the Arizona Libertarian party do it? You can visit their web site and click here to vote. I went as far as a web page, hosted by fairvotelections.com, which asked me for my name, birth year, house address number (i.e., for “600 Main Street”, I would enter “600”), and zip code. Both this web page and the page to which it “posts” its response are “http” pages. No cryptography is used, but then the information you’re sending isn’t terribly secret, either. Do they support Estonian-style vote overriding? Unclear. None of the links or information say a single word about security. The lack of SSL is strongly indicative of a lack of sophistication (although they did set a tracking cookie to an opaque value of some sort).

How about Democrats Abroad? If you go to their web site, you end up at VoteFromAbroad.org, which gives you two choices. You can download a PDF of the ballot, print it and mail or fax it in. Or, you can vote online via the Internet, which helpfully tells you:

Is it safe to vote by Internet? Secure Internet voting is powered by Everyone Counts, a leading expert in high-integrity online elections. We are using the same system the Michigan Democratic Party has used since 2004. Alternatively, you will have the option to vote by post, fax or in-person at Voting Centers in 34 countries around the world.

The registration system, unlike the Arizona one, at least operates over SSL. Regardless, it would seem to have all the same problems. In a public radio interview with Weekend America, Meredith Gowan LeGoff, vice chairman of Democrats Abroad, responded to a question about security issues:

Where I grew up, the dead still vote in Louisiana. There are lots of things that could potentially go wrong in any election. This might be a big challenge to a hacker somewhere. We’re hoping a hacker might care more about democracy than hacking. But we’re not depending on that. We have a lot of processes, and we’ve also chosen an outside vendor, Everyone Counts, to run the online voting.

The best we can do is the same as New Hampshire or Michigan or anywhere else, and that’s to have the members of our list and correspond that to who actually voted. Another important thing to remember is that our ballots are actually public. So you have to give your name and your address, so it’s not secret and it’s not anonymous. It’s probably easier to catch than someone in Mississippi going across to Alabama and trying to vote again.

Ahh, now there’s an interesting choice of security mechanisms. Every vote is public! For starters, this would be completely unacceptable in a general election. It’s debatable what value it has in a party election. Review time: there are two broadly different ways that U.S. political parties select their candidates, and it tends to vary from state to state. Caucuses, most famously used in Iowa, are a very public affair. In the Iowa Democratic caucuses, people stand up, speak their mind, and literally vote with their feet by where they sit or stand in the room. The Iowa Republicans, for contrast, cast their votes secretly. (Wikipedia has all the details.) Primary elections may or may not be anonymous, depending on the state. Regardless, for elections in areas dominated by a single political party, the primary election might as well be the final election, so it’s not hard to argue in favor of anonymous voting in primaries.

On the flip side, maybe we shouldn’t care about voter anonymity. Publish everybody’s name and how they voted in the newspaper. Needless to say, that would certainly simplify the security problem. Whether it would be good for democracy or not, however, is a completely different question.

[Sidebar: bribery and coercion. You don’t have to be a scholar of election history or a crazy conspiracy nut to believe that bribery and coercion are real and pressing issues in elections. Let’s examine the Estonian scheme, described above, for its resistance to bribery to coercion. The fundamental security mechanism used for voter privacy is the ability to vote anew, overriding an earlier vote. Thus, in order to successfully coerce a vote, the coercer must defeat the voter’s ability to vote again. Given that voting requires voters to have their national ID cards, the simplest answer would be to “help” voters vote “correctly”, then collect their ID cards, returning them after the election is over. You could minimize the voter’s inconvenience by doing this on the last possible day to cast a vote.

It’s important to point out that voting in a polling place may still be subject to bribery or coercion. For example, camera-phones with a video mode can record the act of casting a vote on an electronic voting system. Traditional secret-ballot paper systems are vulnerable to a chain-voting attack, where the voter is given a completed ballot before they enter the polls and returns with a fresh, unvoted ballot. Even sophisticated end-to-end voting schemes like ThreeBallot or Punchscan may be subject to equally sophisticated attacks (see these slides from John Kelsey).]

Filed Under: Other Topics, Privacy & Security Tagged With: ,

MySpace Photos Leaked; Payback for Not Fixing Flaw?

January 28, 2008 by

Last week an anonymous person published a file containing half a million images, many of which had been gathered from private profiles on MySpace. This may be the most serious privacy breach yet at MySpace. Kevin Poulsen’s story at Wired News implies that the leak may have been deliberate payback for MySpace failing to fix the vulnerability that allowed the leaks.

“I think the greatest motivator was simply to prove that it could be done,” file creator “DMaul” says in an e-mail interview. “I made it public that I was saving these images. However, I am certain there are mischievous individuals using these hacks for nefarious purposes.”

The MySpace hole surfaced last fall, and it was quickly seized upon by the self-described pedophiles and ordinary voyeurs who used it, among other things, to target 14- and 15-year-old users who’d caught their eye online. A YouTube video showed how to use the bug to retrieve private profile photos. The bug also spawned a number of ad-supported sites that made it easy to retrieve photos. One such site reported more than 77,000 queries before MySpace closed the hole last Friday following Wired News’ report.

…

MySpace plugged a a href=”http://grownupgeek.blogspot.com/2006/08/myspace-closes-giant-security-hole.html”>similar security hole in August 2006 when it made the front page of Digg, four months after it surfaced.

The implication here, not quite stated, is that DMaul was trying to draw attention to the flaw in order to force MySpace to fix it. If this is what it took to get MySpace to fix the flaw, this story reflects very badly on MySpace.

Anyone who has discovered security flaws in commercial products knows that companies react to flaws in two distinct ways. Smart companies react constructively: they’re not happy about the flaws or the subsequent PR fallout, but they acknowledge the truth and work in their customers’ interest to fix problems promptly. Other companies deny problems and delay addressing them, treating security flaws solely as PR problems rather than real risks.

Smart companies have learned that a constructive response minimizes the long-run PR damage and, not coincidentally, protects customers. But some companies seem to lock themselves into the deny-delay strategy.

Now suppose you know that a company’s product has a flaw that is endangering its customers, and the company is denying and delaying. There is something you can do that will force them to fix the problem – you can arrange an attention-grabbing demonstration that will show customers (and the press) that the risk is real. All you have to do is exploit the flaw yourself, get a bunch of private data, and release it. Which is pretty much what DMaul did.

To be clear, I’m not endorsing this course of action. I’m just pointing out why someone might find it attractive despite the obvious ethical objections.

The really interesting aspect of Poulsen’s article is that he doesn’t quite connect the dots and say that DMaul meant to punish MySpace. But Poulsen is savvy enough that he probably wouldn’t have missed the implication either, and he could have written the article to avoid it had he wanted to. Maybe I’m reading too much into the article, but I can’t help suspecting that DMaul was trying to punish MySpace for its lax security.

Filed Under: Uncategorized Tagged With: , ,

New $2B Dutch Transport Card is Insecure

January 21, 2008 by

The new Dutch transit card system, on which $2 billion has been spent, was recently shown by researchers to be insecure. Three attacks have been announced by separate research groups. Let’s look at what went wrong and why.

The system, known as OV-chipkaart, uses contactless smart cards, a technology that allows small digital cards to communicate by radio over short distances (i.e. centimeters or inches) with reader devices. Riders would carry either a disposable paper card or a more permanent plastic card. Riders would “charge up” a card by making a payment, and the card would keep track of the remaining balance. The card would be swiped past the turnstile on entry and exit from the transport system, where a reader device would authenticate the card and cause the card to deduct the proper fare for each ride.

The disposable and plastic cards use different technologies. The disposable card, called Mifare Ultralight, is small, light, and inexpensive. The reusable plastic card, Mifare Classic, uses more sophisticated technologies.

The first attack, published in July 2007, came from Pieter Sieckerman and Maurits van der Schee of the University of Amsterdam, who found vulnerabilities in the Ultralight system. Their main attacks manipulated Ultralight cards, for example by “rewinding” a card to a previous state so it could be re-used. These attacks looked fixable by changing the system’s software, and Sieckerman and van der Schee described the necessary fixes. But it was also evident that a cleverly constructed counterfeit Ultralight card would be able to defeat the system in a manner that would be very difficult to defense.

The fundamental security problem with the disposable Ultralight card is that it doesn’t use cryptography, so the card cannot keep any secrets from an attacker. An attacker who can read a card (e.g., by using standard equipment to emulate a card reader) can know exactly what information is stored on the card, and therefore can make another device that will behave identically to the card. Except, of course, that the attacker’s device can always return itself to the “fully funded” state. Roel Verdult of Raboud University implemented this “cloning” attack and demonstrated it on Dutch television, leading to the recent uproar.

The plastic Mifare Classic card does use cryptography: legitimate cards contain secret keys that they use to authenticate themselves to readers. So attackers cannot straightforwardly clone a card. Mifare Classic was designed to use a secret encryption algorithm.

Karsten Nohl, “Starbug,” and Henryk Plötz announced an attack that involved opening up a Mifare Classic card and capturing a high-resolution image of the circuitry, which they then used to reverse-engineer the cryptographic algorithm. They didn’t publish the algorithm, but their work shows that a real attacker could get the algorithm too.

Unmasking of the algorithm should have been no problem, had the system been engineered well. Kerckhoffs’s Principle, one of the bedrock maxims of cryptography, says that security should never rely on keeping an algorithm secret. It’s okay to have a secret key, if the key is randomly chosen and can be changed when needed, but you should never bank on an algorithm remaining secret.

Unfortunately the designers of Mifare Classic did not follow this principle. Instead, they chose to combine a secret algorithm with a relatively short 48-bit key. This is a problem because once you know the algorithm it’s possible for an attacker to search the entire 48-bit key space, and therefore to forge cards, in a matter or days or weeks. With 48 key bits, there are only about 280 trillion possible keys, which sounds like a lot to the person on the street but isn’t much of a barrier to today’s computers.

Now the Dutch authorities have a mess on their hands. About $2 billion have been invested in this project, but serious fraud seems likely if it is deployed as designed. This kind of disaster would have been less likely had the design process been more open. Secrecy was not only an engineering mistake (violating Kerckhoffs’s Principle) but also a policy mistake, as it allowed the project to get so far along before independent analysts had a chance to critique it. A more open process, like the one the U.S. government used in choosing the Advanced Encryption Standard (AES) would have been safer. Governments seem to have a hard time understanding that openness can make you more secure.

Filed Under: Uncategorized Tagged With:

Could Use-Based Broadband Pricing Help the Net Neutrality Debate?

January 17, 2008 by

Yesterday, thanks to a leaked memo, it came to light that Time Warner Cable intends to try out use-based broadband pricing on a few of its customers. It looks like the plan is for several tiers of use, with the heaviest users possibly paying overage charges on a per-byte basis. In confirming its plans to Reuters, Time Warner pointed out that its heaviest-using five percent of customers generate the majority of data traffic on the network, but still pay as though they were typical users. Under the new proposal, pricing would be based on the total amount of data transferred, rather than the peak throughput on a connection.

If the current, flattened pricing is based on what the connection is worth to a typical customer, who makes only limited use of the connection, then the heaviest five percent of users (let’s call them super-users as shorthand) are reaping a surplus. Bandwidth use might be highly elastic with respect to price, but I think it is also true that the super users do reap a great deal more benefit from their broadband connections than other users do – think of those who pioneer video consumption online, for example.

What happens when network operators fail to see this surplus? They have marginally less incentive to build out the network and drive down the unit cost of data transfer. If the pricing model changed so that network providers’ revenue remained the same in total but was based directly on how much the network is used, then the price would go down for the lightest users and up for the heaviest. If a tiered structure left prices the same for most users and raised them on the heaviest, operators’ total revenue would go up. In either case, networks would have an incentive to encourage innovative, high-bandwidth uses of their networks – regardless of what kind of use that is.

Gigi Sohn of Public Knowledge has come out in favor of Time Warner’s move on these and other grounds. It’s important to acknowledge that network operators still have familiar, monopolistic reasons to intervene against traffic that competes with phone service or cable. But under the current pricing structure, they’ve had a relatively strong argument to discriminate in favor of the traffic they can monetize, and against the traffic they can’t. By allowing them to monetize all traffic, a shift to use based pricing would weaken one of the most persuasive reasons network operators have to oppose net neutrality.

Filed Under: Broadband Tagged With: , , ,