Microsoft has sent out e-mail notifications to nearly 200 million Passport users during the past month urging them to install a patch released nearly two months ago to fix a problem with its Internet Explorer browser.
The patch addresses a vulnerability in IE 5.5 and 6.0 that potentially lets attackers steal confidential information such as credit card numbers from browser cookies.
Microsoft categorized the vulnerability as a critical one and first released a patch addressing the problem on November 13, 2001.
In mid-December, the company sent out e-mail notifications to users with Hotmail and MSN Internet access accounts urging them to install the patch. The company followed that with a similar missive to Passport account holders.
The mailings are part of Microsoft's effort to take a more active "canvassing approach" when it comes to getting users to install recommended patches, a company spokesman said.
"Its pretty commonplace for users not to go out and proactively download patches. So we are going that extra step," the spokesman said.