W32/Mofei-A is a worm which spreads via network shares and contains a backdoor Trojan which allows remote access and control over the computer.
When first run W32/Mofei-A copies itself to the Windows System32 folder as Scardsvr32.exe and drops the file Scardsvr32.dll to the System32 folder. W32/Mofei-A may also drop the files MoFei.dat and MoFei.VER to the System32 folder.
When W32/Mofei-A is run on Microsoft Windows 9x it creates the registry entry
HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices\SCardDrv
= %WINDOWS%\SYSTEM32\Scardsvr32.exe -v
so that Scardsvr32.exe is run automatically each time Windows is started.
When W32/Mofei-A is run on Microsoft Windows NT, 2000 or XP, it replaces the "Smart Card Helper" service and configures this service to run automatically upon startup.