A key way in which banks mitigate the effects of phishing is to have fraudulent websites removed or abusive domain names suspended. This ‘take-down’ is often subcontracted to specialist companies. We analyse six months of ‘feeds’ of phishing website URLs from multiple sources, including two such companies. We demonstrate that in each case huge numbers of websites may be known to others, but the company with the take-down contract remains unaware of them, or only belatedly learns that they exist. We monitored all of the websites to determine when they were removed and calculate the resultant increase in lifetimes from the take-down company not knowing that they should act. The results categorically demonstrate that significant amounts of money are being put at risk by the failure to share proprietary feeds of URLs. We analyse the incentives that prevent data sharing by take-down companies, contrasting this with the anti-virus industry - where sharing prevails - and with schemes for purchasing vulnerability information, where information about attacks is kept proprietary. We conclude by recommending that the defenders of phishing attacks start cooperatively sharing all of their data about phishing URLs with each other.
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