Security firms are in a flap again over the latest virus to attack a Microsoft Office program.

This time the virus is concealed in a malicious PowerPoint attachment that is making the rounds from a Google Gmail address.

Although users have to download an attachment and then open it for to exploit a machine, it seems quite a powerful piece of malware.

The file installs a keylogger and opens up a backdoor so that the hackers can take over a machine to gather keystrokes and install malware.

Then the virus installs a blank PowerPoint presentation so that it looks like nothing has happened.

The BBC is reporting that Asian characters are part of the subject line, so it's likely targeted to the Asian market.

Microsoft just released its latest monthly security patches, so it's likely the virus has been released so that it can do maximum damage before Microsoft is able to protect against.

The Microsoft Security Response Center Blog warns that people should be careful when opening any unexpected PowerPoint file, even from a trusted source.

The statement posted on the blog says: "We've activated our security response process and we have added detection to the Windows Live Safety Center for up-to-date removal of malicious software we've seen that attempts to exploit the vulnerability".