Gates red-faced as Microsoft leaves Apple users exposed to hackers

Microsoft has warned Mac users that a security flaw in Office v.X for the OSX operating system could give malicious hackers access to computers on a network.

The software giant admitted that hackers could shut own copies of the application running on networked Macs.

Microsoft said that malicious programmers can use the software's Network Product Identification (PID) identifier - an anti-piracy mechanism that checks for duplicate serial numbers running on the same network - to close down copies of the application suite.

An announcement on the Microsoft site reads: "A security vulnerability results because of a flaw in the Network PID Checker. Specifically, the Network PID Checker doesn't correctly handle a particular type of malformed announcement."

While Microsoft said the security risk is low, the announcement comes as a slap in the face for Bill Gates who in recent weeks has ordered the company's developers to reassess security.

Gates, chairman and chief software architect at Microsoft, ordered the code scrub as part of the software giant's Trustworthy Computing Initiative aimed at making Windows more reliable and secure.

The clean-up targets the entire Microsoft product portfolio including the recently released .Net tools.

In recent months, key parts of .Net, such as Passport, Instant Messenger and Universal Plug and Play, have fallen victim to high-profile security flaws.