Press Releases

Browse our press release archive

16 Sep 2004

Microsoft warns of critical JPEG image vulnerability, reports Sophos

"Not a pretty picture" - vulnerability affects operating system and programs

Microsoft has described the vulnerability as critical
Microsoft has described the vulnerability as critical

A new critical security vulnerability has been discovered by Microsoft that could enable software viewing JPEG image files (.JPG) to launch malicious code on a user's computer. The security hole could be exploited by hackers or a future internet worm.

Microsoft is recommending that customers patch their computers against the security vulnerability immediately.

"JPEG images are commonly used for graphics on websites and digital photographs so this vulnerability is extremely serious," said Graham Cluley, senior technology consultant for Sophos. "The message, however, is not to panic but to calmly patch your computers now before a virus writer or hacker tries to exploit the loophole and attack innocent users' computers."

A technical bulletin at describes the latest security problem in detail and includes links to patches supplied by Microsoft.

Windows XP SP2 users may still be vulnerable to JPEG flaw

Sophos warns users of Microsoft Windows XP Service Pack 2 that they may still be at risk from the flaw, even though Microsoft has declared the operating system itself does not require an update, as the vulnerability affects programs as well as the operating system.

"Although the Windows XP SP2 operating system is not reported as having the vulnerability, if you are running programs on XP SP2 which contain the flaw - such as Microsoft Office - you could be putting your computer data in danger. It's important that everyone at risk ensures their PC is running the latest security updates," said Cluley.

Keep yourself informed about future vulnerabilities, and ensure your security is up-to-date

Sophos recommends that every IT manager responsible for security should consider subscribing to vulnerability mailing lists such as that operated by Microsoft at

"Home users should consider checking out the services Microsoft offers at, which can scan your home PC for security vulnerabilities and suggest which critical patches need to be installed," continued Cluley.

Sophos continues to recommend computer users practise safe computing as well as running up-to-date anti-virus software.

About Sophos

More than 100 million users in 150 countries rely on Sophos as the best protection against complex threats and data loss. Sophos is committed to providing complete security solutions that are simple to deploy, manage, and use and that deliver the industry's lowest total cost of ownership. Sophos offers award-winning encryption, endpoint security, web, email, mobile and network security solutions backed by SophosLabs - a global network of threat intelligence centers.

Sophos is headquartered in Boston, US and Oxford, UK. More information is available at