After entering into your system, this rootkit paces two files named mrxnet.sys and mrxcls.sys (which are essentially driver files) and instruct your system to mask the threat. Moreover, these files somehow manage to produce certificate signed by Realtek. Detailed information available at Symantec
A normal antivirus program can’t detect and remove this masked virus. If you’re using a free antivirus program just scan your system with Bitdefender Stuxnet Removal Tool. It is free and you can download it from here.