Rugrat is believed to be a "proof of concept" virus written by the same author of at least six other virus "firsts," Symantec said. The virus infects Windows Portable Executable files, including many Windows 64 applications, spreading to files in the same folder as the virus file and in subfolders, Symantec said.Source: InfoWorld
Operating systems that support 64-bit processor chips can accommodate longer basic data units, referred to as "words." Older, 32-bit platforms, such as Windows systems starting with Windows 95, supported words of up to four bytes, which might contain computer instructions or the address of data stored on the computer hard drive. By comparison, 64-bit systems can process eight-byte words and are better suited to processor-intensive demanding tasks such as graphics rendering.
Rugrat does not appear to be designed to spread, but is a "direct-action infector," meaning it stops running immediately after infecting files, Symantec said.
Symantec researchers have linked Rugrat to a family of six viruses called W32.Chiton.gen, which are all believed to be the work of the same author. Each virus in the family demonstrates a different "first ever" infection technique, including W32.Shrug, the first known virus to use the Thread Local Storage structures in Windows NT, 2000 and XP to run virus code, and W32.Chthon, the first virus to run as a native application in Windows NT, 2000 and XP, Symantec said.
Update: Many web sites have stories about the newly found 64bit virus..
But 90% of the sites / stories fail to note that it ONLY affects
IA64 Window. Check Symantec's web site .
Systems Not Affected: DOS, Linux, Macintosh, OS/2, UNIX, Windows 2000, Windows 3.x, Windows 64-bit (AMD64), Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP
Not a lot of Itanium Windows boxes out on the internet.