8/23: W64.Shruggle.1318 Infects PE Files
August 23, 2004

W64.Shruggle.1318 is a direct-action file infector, similar to W64.Rugrat.3344, that infects AMD64 Windows Portable Executable (PE) files.

It is a fairly simple proof-of-concept virus; however, it is the first known virus to attack 64-bit Windows executables on AMD64 systems.

The virus is written in AMD64 assembly code.

Technical details are at Symantec page.