All posts by Tyler Moore

Economics of Cybersecurity MOOC

Security economics is a thriving research discipline, kicked off in 2001 with Ross Anderson’s seminal paper. There has been an annual workshop since 2002. In recent years there has also been an effort to integrate some of the key concepts and findings into course curricula, including in the Part II Security course at Cambridge and my own course at SMU.

We are pleased to announce that on 20 January 2015, we will launch an online course on the Economics of Cybersecurity, as part of edX Professional Education. The course provides a thorough introduction to the field, delivered by leading researchers from Delft University of Technology, University of Cambridge, University of Münster and Southern Methodist UniversityContinue reading Economics of Cybersecurity MOOC

Call for Papers: eCrime Researchers Summit

I have the privilege of serving as co-chair of the program committee for the Anti-Phishing Working Group’s eCrime Researchers Summit, to be held October 23-24 in Las Croabas, Puerto Rico. This has long been one of my favorite conferences to participate in, because it is held in conjunction with the APWG general meeting. This ensures that participation in the conference is evenly split between academia and industry, which leads to in-depth discussions of the latest trends in online crime. It also provides a unique audience for academic researchers to discuss their work, which can foster future collaboration.

Some of my joint work with Richard Clayton appearing at this conference has been discussed on this blog, from measuring the effectiveness of website take-down in fighting phishing to uncovering the frequent lack of cooperation between security firms. As you will see from the call for papers, the conference seeks submissions on all aspects of online crime, not just phishing. Paper submissions are due August 3, so get to work so we can meet up in Puerto Rico this October!
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Fashion crimes: trending-term exploitation on the web

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. Continue reading Fashion crimes: trending-term exploitation on the web

Measuring Search-Redirection Attacks in the Illicit Online Prescription Drug Trade

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.
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Why the Cabinet Office's £27bn cyber crime cost estimate is meaningless

Today the UK Cabinet Office released a report written by Detica. The report concluded that the annual cost of cyber crime in UK is £27bn. That’s less than $1 trillion, as AT&T’s Ed Amoroso testified before the US Congress in 2009. But it’s still a very large number, approximately 2% of UK GDP. If the total is accurate, then cyber crime is a very serious problem of utmost national importance.

Unfortunately, much of the total cost is based on questionable calculations that are impossible for outsiders to verify. 60% of the total cost is ascribed to intellectual property theft (i.e., business secrets not copied music and films) and espionage. The report does describe a methodology for how it arrived at the figures. However, several key details are lacking. To calculate the IP and espionage losses, the authors first calculated measures of each sector’s value to the economy. Then they qualitatively assessed how lucrative and feasible these attacks would be in each sector.

This is where trouble arises. Based on these assessments, the authors assigned a sector-specific probability of theft, one for the best-, worst- and average cases. Unfortunately, these probabilities are not specified in the report, and no detailed rationale is given for their assignment. Are the probabilities based on surveys of firms that have fallen victim to these particular types of crime? Or is it a number simply pulled from the air based on the hunch of the authors? It is impossible to determine from the report.
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Measuring Typosquatting Perpetrators and Funders

For more than a decade, aggressive website registrants have been engaged in ‘typosquatting’ — the intentional registration of misspellings of popular website addresses. Uses for the diverted traffic have evolved over time, ranging from hosting sexually-explicit content to phishing. Several countermeasures have been implemented, including outlawing the practice and developing policies for resolving disputes. Despite these efforts, typosquatting remains rife.

But just how prevalent is typosquatting today, and why is it so pervasive? Ben Edelman and I set out to answer these very questions. In Measuring the Perpetrators and Funders of Typosquatting (appearing at the Financial Cryptography conference), we estimate that at least 938,000 typosquatting domains target the top 3,264 .com sites, and we crawl more than 285,000 of these domains to analyze their revenue sources.
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Call for papers: WEIS 2010 — Submissions due next week

The Workshop on the Economics of Information Security (WEIS) is the leading forum for interdisciplinary scholarship on information security, combining expertise from the fields of economics, social science, business, law, policy and computer science. Prior workshops have explored the role of incentives between attackers and defenders, identified market failures dogging Internet security, and assessed investments in cyber-defense.

The ninth installment of WEIS will take place June 7–8 at Harvard. Submissions are due in one week, February 22, 2010. For more information, see the complete call for papers.

WEIS 2010 will build on past efforts using empirical and analytic tools to not only understand threats, but also strengthen security through novel evaluations of available solutions. How should information risk be modeled given the constraints of rare incidence and high interdependence? How do individuals’ and organizations’ perceptions of privacy and security color their decision making? How can we move towards a more secure information infrastructure and code base while accounting for the incentives of stakeholders?

If you have been working to answer questions such as these, then I encourage you to submit a paper.

Temporal Correlations between Spam and Phishing Websites

Richard Clayton and I have been studying phishing website take-down for some time. We monitored the availability of phishing websites, finding that while most phishing websites are removed with a day or two, a substantial minority remain for much longer. We later found that one of the main reasons why so many websites slip through the cracks is that the take-down companies responsible for removal refuse to share their URL lists with each other.

One nagging question remained, however. Do long-lived phishing websites cause any harm? Would removing them actually help? To get that answer, we had to bring together data on the timing of phishing spam transmission (generously shared by Cisco IronPort) with our existing data on phishing website lifetimes. In our paper co-authored with Henry Stern and presented this week at the USENIX LEET Workshop in Boston, we describe how a substantial portion of long-lived phishing websites continue to receive new spam until the website is removed. For instance, fresh spam continues to be sent out for 75% of phishing websites alive after one week, attracting new victims. Furthermore, around 60% of phishing websites still alive after a month keep receiving spam advertisements.

Consequently, removal of websites by the banks (and the specialist take-down companies they hire) is important. Even when the sites stay up for some time, there is value in continued efforts to get them removed, because this will limit the damage.

However, as we have pointed out before, the take-down companies cause considerable damage by their continuing refusal to share data on phishing attacks with each other, despite our proposals addressing their competitive concerns. Our (rough) estimate of the financial harm due to longer-lived phishing websites was $330 million per year. Given this new evidence of persistent spam campaigns, we are now more confident of this measure of harm.

There are other interesting insights discussed in our new paper. For instance, phishing attacks can be broken down into two main categories: ordinary phishing hosted on compromised web servers and fast-flux phishing hosted on a botnet infrastructure. It turns out that fast-flux phishing spam is more tightly correlated with the uptime of the associated phishing host. Most spam is sent out around the time the fast-flux website first appears and stops once the website is removed. For phishing websites hosted on compromised web servers, there is much greater variation between the time a website appears and when the spam is sent. Furthermore, fast-flux phishing spam was 68% of the total email spam detected by IronPort, despite this being only 3% of all the websites.

So there seems to be a cottage industry of fairly disorganized phishing attacks, with perhaps a few hundred people involved. Each compromises a small number of websites, while sending a small amount of spam. Conversely there are a small number of organized gangs who use botnets for hosting, send most of the spam, and are extremely efficient on every measure we consider. We understand that the police are concentrating their efforts on the second set of criminals. This appears to be a sound decision.

How can we co-operate to tackle phishing?

Richard Clayton and I recently presented evidence of the adverse impact of take-down companies not sharing phishing feeds. Many phishing websites are missed by the take-down company which has the contract for removal; unsurprisingly, these websites are not removed very fast. Consequently, more consumers’ identities are stolen.

In the paper, we propose a simple solution: take-down companies should share their raw, unverified feeds of phishing URLs with their competitors. Each company can examine the raw feed, pick out the websites impersonating their clients, and focus on removing these sites.

Since we presented our findings to the Anti-Phishing Working Group eCrime Researchers Summit, we have received considerable feedback from take-down companies. Take-down companies attending the APWG meeting understood that sharing would help speed up response times, but expressed reservations at sharing their feeds unless they were duly compensated. Eric Olsen of Cyveillance (another company offering take-down services) has written a comprehensive rebuttal of our recommendations. He argues that competition between take-down companies drives investment in efforts to detect more websites. Mandated sharing of phishing URL feeds, in his view, would undermine these detection efforts and cause take-down companies such as Cyveillance to exit the business.

I do have some sympathy for the objections raised by the take-down companies. As we state in the paper, free-riding (where one company relies on another to invest in detection so they don’t have to) is a concern for any sharing regime. Academic research studying other areas of information security (e.g., here and here), however, has shown that free-riding is unlikely to be so rampant as to drive all the best take-down companies out of offering service, as Mr. Olsen suggests.

While we can quibble over the extent of the threat from free free-riding, it should not detract from the conclusions we draw over the need for greater sharing. In our view, it would be unwise and irresponsible to accept the current status quo of keeping phishing URL feeds completely private. After all, competition without sharing has approximately doubled the lifetimes of phishing websites! The solution, then, is to devise a sharing mechanism that gives take-down companies the incentive to keep detecting more phishing URLs.
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