Bitcoin Exchange In China – Gameover?
by
Etay Maor

 

Cybercriminals’ 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, as well as making BTC China the largest Bitcoin exchange. While a recent 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 cybercriminals going after the consumers who use Bitcoins. Our security team has recently analyzed a malware variant that actively targets BTC China and other Bitcoin exchanges.

In our previous blog we discussed how cybercriminals use Bitcoins to anonymize their transactions while simultaneously also targeting the currency for financial gain. In the blog, we discussed how a Citadel variant we discovered targets and takes screenshots of various virtual currencies platforms and Bitcoin related sites, as well as underground discussions revolving around the hacking of Bitcoin exchanges. Our security team has recently analyzed a Zeus P2P/Gameover variant that actively targets BTC China, as can be seen in the extracted code snippet below:

<WebInjects index=”702″ compressed=”0″>
<RedirUrl><![CDATA[http://$_PROXY_SERVER_HOST_$/script0.js]]></RedirUrl>
</WebInjects>

<Pattern><![CDATA[/^Error! Hyperlink reference not valid..|)btcchina\.com\/bbs\/index\.php/iAU]]></Pattern>

<!– STRINGS:  https:// vip. btcchina.com/bbs/index.php –>

This Gameover variant waits until an infected user attempts to log into the BTC China website. When this occurs, the malware steals the victim’s username and password and suspends the session temporarily. Once the cybercriminal has the victim’s credentials he can easily perform an account takeover and assume control of the Bitcoins associated with the account. The reason for pausing the session is that the cybercriminal may need to ask the victim for their 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 a lucrative target not only for stealing Bitcoins, but 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 cybercriminals, whether they see Bitcoins as a platform or a target, are not keen on keeping their capital in Bitcoins. Rather, criminals 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 an additional anti-trace back step. It seems cybercriminals are not Bitcoins 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 currency we can expect to see more Man in the Browser (MitB) malware variants targeting Bitcoin exchanges and related sites.

 

 

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