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.
Continue reading How can we co-operate to tackle phishing? →

Tyler Moore and I are presenting another one of our academic phishing papers today at the Anti-Phishing Working Group’s Third eCrime Researchers Summit here in Atlanta, Georgia. The paper “The consequence of non-cooperation in the fight against phishing” (pre-proceedings version here) goes some way to explaining anomalies we found in our previous analysis of phishing website lifetimes. The “take-down” companies reckon to get phishing websites removed within a few hours, whereas our measurements show that the average lifetimes are a few days.

These “take-down” companies are generally specialist offshoots of more general “brand protection” companies, and are hired by banks to handle removal of fake phishing websites.

When we examined our data more carefully we found that we were receiving “feeds” of phishing website URLs from several different sources — and the “take-down” companies that were passing the data to us were not passing the data to each other.

So it often occurs that take-down company A knows about a phishing website targeting a particular bank, but take-down company B is ignorant of its existence. If it is company B that has the contract for removing sites for that bank then, since they don’t know the website exists, they take no action and the site stays up.

Since we were receiving data feeds from both company A and company B, we knew the site existed and we measured its lifetime — which is much extended. In fact, it’s somewhat of a mystery why it is removed at all! Our best guess is that reports made directly to ISPs trigger removal.

The paper contains all the details, and gives all the figures to show that website lifetimes are extended by about 5 days when the take-down company is completely unaware of the site. On other occasions the company learns about the site some time after it is first detected by someone else; and this extends the lifetimes by an average of 2 days.

Since extended lifetimes equate to more unsuspecting visitors handing over their credentials and having their bank accounts cleaned out, these delays can also be expressed in monetary terms. Using the rough and ready model we developed last year, we estimate that an extra $326 million per annum is currently being put at risk by the lack of data sharing. This figure is from our analysis of just two companies’ feeds, and there are several more such companies in this business.

Not surprisingly, our paper suggests that the take-down companies should be sharing their data, so that when they learn about websites attacking banks they don’t have contracts with, they pass the details on to another company who can start to get the site removed.

We analyse the incentives to make this change (and the incentives the companies have not to do so) and contrast the current arrangements with the anti-virus/malware industry — where sample suspect code has been shared since the early 1990s.

In particular, we note that it is the banks who would benefit most from data sharing — and since they are paying the bills, we think that they may well be in a position to force through changes in policy. To best protect the public, we must hope that this happens soon.