W32.Qudos

W32.Qudos is an encrypted Win32 virus that infects Windows Portable Executable (PE) files that have .exe, .dll. or .ocx extensions that are in the same folder as the virus or in the \Windows folder.

It is a slow infector that infects only up to 20 PE files in each of the two folders each time that it runs. Each file has a 15 percent chance of being infected.

NOTE: Definitions dated prior to July 22, 2002 detect this threat as Bloodhound.W32.1.




What are Portable Executable (PE) files?
PE files are files that are portable across all Microsoft 32-bit operating systems. The same PE-format executable can be executed on any version of Windows 95, 98, Me, NT, and 2000. Therefore, all PE files are executable, but not all executable files are portable.

A good example of a Portable Executable is a screen saver (.scr) file.