Over a year ago, we blogged about a bug at Gawker which replaced all non-ASCII characters in passwords with ‘?’ prior to checking. Along with Rubin Xu and others I’ve investigated issues surrounding passwords, languages, and character encoding throughout the past year. This should be easy: websites using UTF-8 can accept any password and hash it into a standard format regardless of the writing system being used. Instead though, as we report a new paper which I presented last week at the Web 2.0 Security and Privacy workshop in San Francisco, passwords still localise poorly both because websites are buggy and users have been trained to type ASCII passwords only. This has broad implications for passwords’ role as a “universal” authentication mechanism. (more…)
Posts filed under 'Web security
Two years ago, Hyoungshick Kim, Jun Ho Huh and I wrote a paper On the Security of Internet banking in South Korea in which we discussed an IT security policy that had gone horribly wrong. The Government of Korea had tried in 1998 to secure electronic commerce by getting all the banks to use an officially-approved AciveX plugin, effectively locking most Koreans into IE. We argued in 2010 that this provided less security than it seemed, and imposed high usability and compatibility costs. Hyoungshick presented our paper at a special conference, and the government withdrew the ActiveX mandate.
It’s now apparent that the problem is still there. The bureaucracy created a procedure to approve alternative technologies, and (surprise) still hasn’t approved any. Korean web businesses remain trapped in the bubble, and fall farther and farther behind. This may well come to be seen as a warning to other governments to adopt true open standards, if they want to avoid a similar fate. The Cabinet Office should take note – and don’t forget to respond to their consultation!
Using a multi-word “passphrase” instead of a password has been suggested for decades as a way to thwart guessing attacks. The idea is now making a comeback, for example with the Fastwords proposal which identifies that mobile phones are optimised for entering dictionary words and not random character strings. Google’s recent password advice suggests condensing a sentence to form a password, while Komanduri et al.’s recent lab study suggests simply requiring longer passwords may be the best security policy. Even xkcd espouses multi-word passwords (albeit with randomly-chosen words). I’ve been advocating through my research though that authentication schemes can only be evaluated by studying large user-chosens distribution in the wild and not the theoretical space of choices. There’s no public data on how people choose passphrases, though Kuo et al.’s 2006 study for mnemonic-phrase passwords found many weak choices. In my recent paper (written with Ekaterina Shutova) presented at USEC last Friday (a workshop co-located with Financial Crypto), we study the problem using data crawled from the now-defunct Amazon PayPhrase system, introduced last year for US users only. Our goal wasn’t to evaluate the security of the scheme as deployed by Amazon, but learn more how people choose passphrases in general. While this is a relatively limited data source, our results suggest some caution on this approach. (more…)
Continuing its heritage of innovating in the area of security research, FreeBSD 9.0 introduces Capsicum. Capsicum is a lightweight framework which extends a POSIX UNIX kernel to support new security capabilities and adds a userland sandbox API. Originally developed as a collaboration between the University of Cambridge Computer Laboratory and Google and sponsored by a grant from Google, FreeBSD was the prototype platform and Chromium was the prototype application. FreeBSD 9.0 provides kernel support as an experimental feature for researchers and early adopters. Application support will follow in a later FreeBSD release and there are plans to provide some initial Capsicum-protected applications in FreeBSD 9.1.
“Google is excited to see the award-winning Capsicum work incorporated in FreeBSD 9.0, bringing native capability security to mainstream UNIX for the first time,” said Ulfar Erlingsson, Manager, Security Research at Google.
We first wrote about Capsicum, a hybridisation of the capability system security model with POSIX operating system semantics developed with support from Google, in Capsicum: practical capabilities for UNIX (USENIX Security 2010 and ;login magazine). Capsicum targets the problem of operating system support for application compartmentalisation — the restructuring of applications into a set of sandboxed components in order to enforce policies and mitigate security vulnerabilities. While Capsicum’s hybrid capability model is not yet used by the FreeBSD userspace, experimental kernel support will make Capsicum more accessible to researchers and software developers interested in deploying application sandboxing. For example, the Policy Weaving project at the University of Wisconsin has been investigating automated application compartmentalisation in support of security policy enforcement using Capsicum.
Google recently launched a major advertising campaign around its “Good to Know” guides to online safety and privacy. Google’s password advice has appeared on billboards in the London underground and a full-page ad in The Economist. Their example of a “very strong password” is ‘2bon2btitq’, taken from the famous Hamlet quote “To be or not to be, that is the question”.
Empirically though, this is not a strong password-it’s almost exactly average! (more…)
News travels fast. Blogs and other websites pick up a news story only about 2.5 hours on average after it has been reported by traditional media. This leads to an almost continuous supply of new “trending” topics, which are then amplified across the Internet, before fading away relatively quickly. Many web companies track these terms, on search engines and in social media.
However narrow, these first moments after a story breaks present a window of opportunity for miscreants to infiltrate web and social network search results in response. The motivation for doing so is primarily financial. Websites that rank high in response to a search for a trending term are likely to receive considerable amounts of traffic, regardless of their quality.
In particular, the sole goal of many sites designed in response to trending terms is to produce revenue through the advertisements that they display in their pages, without providing any original content or services. Such sites are often referred to as “Made for AdSense” (MFA) after the name of the Google advertising platform they are often targeting. Whether such activity is deemed to be criminal or merely a nuisance remains an open question, and largely depends on the tactics used to prop the sites up in the search-engine rankings. Some other sites devised to respond to trending terms have more overtly sinister motives. For instance, a number of malicious sites serve malware in hopes of infecting visitors’ machines, or peddle fake anti-virus software.
Together with Nektarios Leontiadis and Nicolas Christin, I have carried out a large-scale measurement and analysis of trending-term exploitation on the web, and the results are being presented at the ACM Conference on Computer and Communications Security (CCS) in Chicago this week. Based on a collection of over 60 million search results and tweets gathered over nine months, we characterize how trending terms are used to perform web search-engine manipulation and social-network spam. The full details can be found in the paper and presentation. (more…)
Last week, in retaliation against the heavy-handed response to planned protests against the BART metro system in California, the hacktivist group Anonymous hacked into several BART servers. They leaked part of a database of users from myBART, a website which provides frequent BART riders with email updates about activities near BART stations. An interesting aspect of the leak is that 1,346 of the 2,002 accounts seem to have randomly-generated passwords-a rare opportunity to study this approach to password security. (more…)
The usability community has long complained about the problems of passwords (remember the Adams and Sasse classic). These days, even our beloved XKCD has something to say about the difficulties of coming up with a password that is easy to memorize and hard to brute-force. The sensible strategy suggested in the comic, of using a passphrase made of several common words, is also the main principle behind Jakobsson and Akavipat’s fastwords. It’s a great suggestion. However, in the long term, no solution that requires users to remember secrets is going to scale to hundreds of different accounts, if all those remembered secrets have to be different (and changed every couple of months).
This is why, as I previously blogged, I am exploring the space of solutions that do not require the memorization of any secrets—whether passwords, passphrases, PINs, faces, graphical squiggles or anything else. My SPW paper, Pico: No more passwords, was finalized in June (including improvements suggested in the comments to the previous blog post) and I am about to give an invited talk on Pico at Usenix Security 2011 in San Francisco.
Usenix talks are recorded and the video is posted next to the abstracts: if you are so inclined, you will be able to watch my presentation shortly after I give it.
To encourage adoption, I chose not to patent any aspect of Pico. If you wish to collaborate, or fund this effort, talk to me. If you wish to build or sell it on your own, be my guest. No royalties due—just cite the paper.
Unauthorized online pharmacies that sell prescription drugs without requiring a prescription have been a fixture of the web for many years. Given the questionable legality of the shops’ business models, it is not surprising that most pharmacies resort to illegal methods for promoting their wares. Most prominently, email spam has relentlessly advertised illicit pharmacies. Researchers have measured the conversion rate of such spam, finding it to be surprisingly low. Upon reflection, this makes sense, given the spam’s unsolicited and untargeted nature. A more successful approach for the pharmacies would be to target users who have expressed an interest in purchasing drugs, such as those searching the web for online pharmacies. The trouble is that dodgy pharmacy websites don’t always garner the highest PageRanks on their own merits, and so some form of black-hat search-engine optimization may be required in order to appear near the top of web search results.
Indeed, by gathering daily the top search web results for 218 drug-related queries over nine months in 2010-2011, Nektarios Leontiadis, Nicolas Christin and I have found evidence of substantial manipulation of web search results to promote unauthorized pharmacies. In particular, we find that around one-third of the collected search results were one of 7,000 infected hosts triggered to redirect to a few hundred pharmacy websites. In the pervasive search-redirection attacks, miscreants compromise high-ranking websites and dynamically redirect traffic different pharmacies based on the particular search terms issued by the consumer. The full details of the study can be found in a paper appearing this week at the 20th USENIX Security Symposium in San Francisco.
Back in January I visited TalkTalk along with Jim Killock of the Open Rights Group (ORG) to have their new Internet blocking system explained to us. The system was announced yesterday, and I’m now publishing my technical description of how it works (note that it was called “BrightFeed” when we saw it, but is now named “HomeSafe”).
Buried in all the detail of how the system works are two key points — the first is the notion that it is possible for a centralised checking system (especially one that tells a remote site its identity) to determine whether sites are malicious are not. This is problematic and I doubt that malware distributors will see this as much of a challenge — although on the other hand, perhaps by setting your browser’s User Agent string to pretend to be the checking system you might become rather safer!
The second is that although the system is described as “opt in”, that only applies to whether or not websites you visit might be blocked. What is not “opt in” is whether or not TalkTalk learns the details of the URLs that all of their customers visit, whether they have opted in or not. All of these sites will be visited by TalkTalk’s automated system — which may take some explaining if the remote system told you a URL in confidence and is checking their logs to see who visits.
On their site, ORG have expressed an opinion as to whether the system can be operated lawfully, along with TalkTalk’s own legal analysis. TalkTalk argue that the system’s purpose is to protect their network, which gives them a statutory exemption from wire-tapping legislation; whereas all the public relations material seems to think it’s been developed to protect the users….
… in the end though, the system will be judged by its effectiveness, and in a world where less than 20% of new threats are detected — that may not be all that high.