MS fixes 'moderate' IE bug experts say is serious

Microsoft late Wednesday issued a patch to fix a flaw in Internet Explorer (IE) that it says poses only a "moderate" risk to users. Security experts, however, say the vulnerability is serious and could be exploited to take over a user's machine.

The flaw affects IE 5.5 and IE 6.0 and lies in a feature meant to set up security boundaries between Web browser windows and the local system. Exploiting it could enable an attacker to read information on a user's computer and invoke programs already on the PC, according to Microsoft in security bulletin MS02-068. (

"This is an extensive downplaying of the severity," says Thor Larholm, a Copenhagen-based security researcher with PivX Solutions LLC. "An attacker can in fact take any action on a system a local user could, including modifying files, formatting the hard drive and uploading applications."

This "external object caching" vulnerability was first made public in late October by Israeli security company GreyMagic Software together with a score of other IE flaws.

An attacker could exploit the flaw by luring a user to an especially coded Web page or sending that page via HTML (Hypertext Markup Language) e-mail, Microsoft said. The company advises users to consider applying the patch, which is part of a super patch that includes all previous IE 5.5 and IE 6.0 fixes.

Larholm, who has close ties to GreyMagic, warns that an exploit for the external object caching flaw will likely be out soon, since the flaw was first made public in October. He urges users to patch up as soon as possible. Another 18 publicly known but unpatched vulnerabilities remain in IE, of which six are serious, Larholm said.

Microsoft changed the way it rates security issues last month because customers complained they could not identify the most serious vulnerabilities, the company has said.

Under the new system, fewer bulletins get the "critical" stamp. The only vulnerabilities now rated critical are those that could be exploited to allow malicious Internet worms to spread without user action. Many issues that were previously rated critical are now "important," a new category in the rating system. Important vulnerabilities could expose user data or threaten system resources.

Rated "moderate" are vulnerabilities that are difficult to exploit because of default configuration, auditing, or just plain difficulty of exploitation, according to Microsoft's rating scheme.

Join the newsletter!


Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Joris Evers

IDG News Service
Show Comments

Brand Post

Most Popular Reviews

Latest Articles


PCW Evaluation Team

Luke Hill


I need power and lots of it. As a Front End Web developer anything less just won’t cut it which is why the MSI GT75 is an outstanding laptop for me. It’s a sleek and futuristic looking, high quality, beast that has a touch of sci-fi flare about it.

Emily Tyson

MSI GE63 Raider

If you’re looking to invest in your next work horse laptop for work or home use, you can’t go wrong with the MSI GE63.

Laura Johnston

MSI GS65 Stealth Thin

If you can afford the price tag, it is well worth the money. It out performs any other laptop I have tried for gaming, and the transportable design and incredible display also make it ideal for work.

Andrew Teoh

Brother MFC-L9570CDW Multifunction Printer

Touch screen visibility and operation was great and easy to navigate. Each menu and sub-menu was in an understandable order and category

Louise Coady

Brother MFC-L9570CDW Multifunction Printer

The printer was convenient, produced clear and vibrant images and was very easy to use

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?