Microsoft has released a security update for its Word RTF (Rich Text Format) formatting.

The company's implementation of RTF for Mac and for Windows gave hackers the chance of executing commands via RTF using macro templates. The macro vulnerability is transported in Word files.

It works by linking documents to a template file containing macros. Placing a macro file in a template sidesteps Word's ability to warn users when opening documents containing macros. The security update informs users when they are opening a template containing macros.

Running a macro without warning can damage data or allow unauthorized retrieval of data from a system when visiting a Web site or opening an e-mail message.

The update is for Word 98 and 2001 for Mac. It's available for download from Microsoft.