Stuxnet was kidnapping the Siemens .DLL and putting the doppelgänger in its place to hijack the system. It did this by changing the name of the Siemens .DLL from s7otbxdx.DLL to s7otbxsx.DLL and installing the rogue .DLL with the original’s name in its place, essentially stealing its identity. Then when the system called up the Siemens .DLL to perform any action, the malicious .DLL answered instead.
