tokens: The malware takes these steps : Check if the system master boot record ( MBR ) contains an infection marker ( 0xD289C989C089 8-bytes value at offset 0x2C ) , and , if so , terminate itself Check again if the process is attached to a debugger ( using the techniques described previously ) Read , decrypt , and map the stage 5 malware ( written in the previous stage in msvcr90.dll ) Open winlogon.exe process Load user32.dll system library and read the KernelCallbackTable pointer from its own process environment block ( PEB ) ( Note : The KernelCallbackTable points to an array of graphic functions used by Win32 kernel subsystem module win32k.sys as call-back into user-mode .