Users of Coinbase, a Silicon Valley-funded startup that offers some Bitcoin banking services, have become the target of phishing attacks. The booming virtual currency has grown into an increasingly appealing target for hackers, soaring from a valuation of around $13 each at the beginning of January to around $140 currently. Earlier today it was found that some Coinbase users' transaction records were discoverable by search engines, and the company believes that the attackers used this information to acquire its targets. The records note what a user purchased and how much they paid, in addition to providing their email address, a particularly big problem for a currency that's often traded anonymously.

Bitcoinleak

A Coinbase user's transaction record, product information, and email address exposed through a search result link.

The leaked information became available as a result of publicly posted links by users, and Coinbase is now working to alter how these pages work. The company announced in February that it had sold over $1 million of Bitcoin across the prior 30 days, but as value of the currency rises, so do concerns over a bursting economic bubble. A major crash occurred in 2011, bringing the currency's value down 90 percent in the wake of a spate of security issues, including the hacking of Mt. Gox, the largest name in Bitcoin trading. While phishing attacks aren't uncommon, security is a major concern for an unbacked currency like Bitcoin.