According to Kaspersky Lab, the TDL4 by the TDSS gang is the most dangerous botnet because it can install itself to the master boot record. This allows the botnet to infect all versions of Windows (32 or 64 bit). It has been said that ¼ of all computers in the United States are infected.
TDL4 main purpose is to install an executable called conhost.exe to Bitcoin mine. Bitcoin is a free open-source peer-peer program to make payments to anyone in the world no matter what currency. This skips having to use the banks to transfer money. This allows TDSS to view all transactions made by users infected with TDL4. Cyber criminals are getting more and more interested in Bitcoin because of its lacked security.
Even though TDL4 is hard to detect and almost impossible to remove, there are ways to defend yourself against this. You can either have a good anti-virus to detect the executable or download Kaspersky Lab’s standalone tool that removes most of the botnet’s variants. To fight this problem in future version of Windows, Microsoft is making all boot components authenticate during start up in Windows 8.