Microsoft tells US Air Force to bug off

Outlook patch is patchy

Microsoft's security patch for Outlook, which is designed to protect users from the effects of another Love Bug-style virus, has come under fire from no less a body than the US Air Force.

In a paper to be presented at a security workshop in June, an assistant professor of computer science at the US Air Force Academy will deliver a devastating critique of Microsoft's approach to security in general and Outlook in particular.

Martin Carlisle will tell an audience of security experts that a security patch to Outlook, which is designed to stop viruses spreading via automated messages through requiring user's authorisation via a dialog box, can be easily circumvented.

This "Object Model Guard" prompts a user with a dialogue box when an external program tries to access a user's Outlook address book, a trick used by the Love Bug and other similar viruses.

Carlisle said this idea has promise but Microsoft's implementation is flawed.

"It is possible, with a small amount of code, to create a program that hides and answers the dialog box automatically," said Carlisle.

In a paper to be presented at the workshop Carlisle explains how Microsoft dismissed the significance of the potential vulnerability. Its security team argues that to get around the dialog box they would have to get executable code running on a victims machine, and if an attacker could do that getting around the dialog box would be "the least of your worries".

This, frankly astonishingly arrogant response, is given short shrift by Carlisle: "The Microsoft Security Team seem to have missed the significance of their own security patch because their view neglects the ability of viruses of this class to replicate."

Carlisle and colleague (and co-author) Scott Studer have produced a detailed rebuttal of Microsoft's argument and suggestions of improvement to the dialogue box security, which involve protecting the lowest level of an application.

In a statement we find hard to disagree with the researchers state that reinforcing dialogs based security in Windows can only go so far.

"Given the current limitations of the Windows operating system, this [improving dialogue box security] turns to be similar to trying to secure a parked car at an airport. You can make it harder to break in but you can never make you car totally secure."

The researchers said that Microsoft should consider modifying its operating system in order to verify that messages received come from users rather than other programs. Carlisle and Studer also cover a variety of other ideas for dealing with Love Bug-style viruses (such as blocking Visual Basic Scripting) and their paper is well worth a read. ®

External links

USAF paper: Reinforcing Dialog-Based Security

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