Cyber criminals’ interest in bitcoin has continued to grow alongside the mainstream media’s heavy coverage of the currency and its high rate of adoption by both consumers and businesses. The surge in demand for bitcoins in the Chinese market led to the currency’s sharp increase in value while making BTC China the largest bitcoin exchange. While a ban by the Chinese government on dealing with third-party bitcoin exchanges has already taken its toll on the currency’s value, we’ve also seen cyber criminals going after the consumers who use bitcoins. The IBM Trusteer security team recently analyzed a malware variant that actively targets BTC China and other platforms for bitcoin exchange.

In a previous article, we discussed how cyber criminals use bitcoins to anonymize their transactions while simultaneously targeting the currency for financial gain. We also discussed how a Citadel variant that we discovered targets and takes screenshots of various virtual currency platforms and bitcoin-related sites as well as underground discussions revolving around the hacking of bitcoin exchanges.

The IBM Trusteer security team examined a Zeus P2P/Gameover variant that actively targets BTC China, as can be seen in the extracted code snippet below:

This Gameover variant waits until an infected user attempts to log in to the BTC China website. When this occurs, the malware steals the victim’s password and username and suspends the session temporarily. Once the cyber criminal has the victim’s credentials, he or she can easily perform an account takeover and assume control of the bitcoins associated with the account.

Bitcoin Exchange via Password Exchange

The reason for pausing the session is that the cyber criminal may need to ask the victim for his or her one-time password (OTP). To do so, the malware will use simple social engineering techniques combined with HTML injection and present the victim with a request for the OTP under the false pretense of a security measure.

Bitcoin accounts are not just a lucrative target for stealing bitcoins; they can also be used for laundering money from accounts that have been taken over, as recently demonstrated by a Dutch gang. So far, it is worth noting that most cyber criminals, whether they see bitcoin exchange as a platform or a target, are not keen on keeping their capital in bitcoins. Rather, they use the currency as a middleman for laundering funds without leaving any tracks. They sometimes use additional services such as the Tor hidden service “Bitcoin Fog Company” as another way to fight trace-backs.

Cyber criminals are clearly not bitcoin’s value speculators — they are interested in quickly monetizing stolen bitcoins or using them as a money laundering mechanism. With the growing use and popularity of this form of currency, we can expect to see more Man-in-the-Browser (MitB) malware variants targeting bitcoin exchanges and related sites.

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