Recently, we began to notice that some hacked websites were redirecting traffic from certain browsers to the BitCoin site, bitcoin.org. What’s going on? Is Bitcoin using black hat SEO? Is their site malicious?
As you can see, the hacked website doesn’t redirect to bitcoin.org directly. It first redirects to 194 .6 .233 .7/mxjbb . cgi?default, which acts a at raffic directing system (TDS). This piece analyzes request parameters specific to the visitor (IP, browser, referrer, etc.) and makes a decision as to what to do with the particular request. The TDS may have different routes for users from different countries or users with different browsers. Furthermore, the TDS may be completely uninterested in certain requests (e.g. requests from search engine and security bots, or requests from browsers that can be very hard to exploit). A typical TDS would either return some HTTP error (e.g. 404 Page Not Found) or redirect unwanted traffic to some neutral third-party site. Most TDS are configured to dump unwanted traffic to google.com.