Hackers continue to experiment with 64-bit viruses

Another virus aimed at the cluster of current 64-bit computer users has been detected by antivirus specialists.

Written in AMD 64-bit assembly code, the Shruggle virus tries to infect Windows Portable Executable (PE) files on AMD systems. Once on a system it searches for PE files and attaches itself to them.

Shruggle is similar in design to Rugrat, the first 64-bit virus. It is not known at this point if the author of both pieces of malicious code is the same person.

"It's more of a proof of concept and isn't really a threat," said Graham Cluley, senior technology consultant at Sophos.

"32-bit viruses are going to be far more common for a while, and there aren't the 64-bit systems for this to spread. These viruses have a tougher time spreading than those aimed at 32-bit systems. Perhaps it is a taste of things to come, however."

Although Shruggle does not infect standard 32-bit systems, it will function on a 32-bit computer running 64-bit emulation software.

Symantec, which discoverd the virus, said that it was identified on a newsgroup and that fewer than 50 cases have been reported.