Virus writers focus on image bug

A critical weakness found in many Microsoft programs looks like it is about to be exploited by virus writers.
The bug only came to light last week, but code is now circulating that could be used to attack vulnerable machines.

Some security experts said conditions were right to turn the bug into a widely exploited problem.

But others said there was still time to patch machines and ensure that virus writers were prevented from scoring a big success.

Picture problems

Microsoft issued a critical security alert last week telling users that there were problems with the way Jpeg images are handled by Windows and many other programs it makes.

The alert said that, theoretically, a malicious attacker could take over a vulnerable machine using a carefully crafted image that contained code to exploit the bug.

At the time the alert was issued, example code to exploit the bug had not been seen.

However, sample code written for the bug appeared earlier this week, leading some to speculate that a virus written to use it would follow soon.

The code was posted to a closed circulation security mailing list and a publicly viewable website.

This could mean that users find their machine under attack when they view images on the web or when their e-mail program previews images contained in messages.

"This is the virus equivalent of a harmonic convergence," said David Perry, from anti-virus firm Trend Micro.

He said all the conditions were right to make any virus that used the exploit code a big hitter.

"It's been a long time since the last major virus outbreak," he said. "That's a major factor. How many people have let their guard down?"

"Also," he said, "it's a big vulnerability and it affects a lot of different people and it would be easy to put on the web or any of a number of different things."

He said porn sites or those happy to spread spyware could be sources of virus carrying images.

No panic

He said one other reason for suspecting that a virus to exploit the Jpeg bug was imminent was the fact that the annual Virus Bulletin conference runs this week.

"There's almost always a virus released during the Virus Bulletin conference because all the virus experts are away from home," he said.

But Graham Cluley from anti-virus firm Sophos said there was no need to panic.

"At the moment no-one is exploiting the bug to deliver malicious code," he told BBC News Online. "It is purely being done as a 'proof of concept'."

He urged people to apply patches before a virus was written to exploit the bug.

"Microsoft has had its patches out for more than a week now," he said, "so home users who have switched to automated updates should already have downloaded the fix."

Security experts pointed out that machines patched with the SP2 update to XP, which closes many commonly exploited vulnerabilities, could be at risk from the Jpeg virus if they used other programs that still contained the loophole.

In all, more than a dozen programs are susceptible to the Jpeg exploit.

Advice from analysts Gartner said the Jpeg bug could be hard for companies to protect themselves against because most computers had several versions of the vulnerable component installed.

http://news.bbc.co.uk/1/hi/technology/3684552.stm

Poison porn pics show up online

The first images crafted to contain a malicious program that can take control of a PC have been found on the net.
Security experts have been expecting such images to turn up after Microsoft revealed a weakness in the way Windows handles the popular Jpeg format.

Soon after this discovery, a program started circulating online that was written to exploit this bug.

The poisoned images were posted to a porn newsgroup at the weekend and were found by Usenet provider Easynews.

Early warning

Poisoned pictures containing the bug have been widely predicted following the discovery of the Jpeg bug that afflicts more than a dozen Microsoft programs.

To fall victim to the poisoned pictures, users must view it using Windows Explorer.

Once in place, the code then tells an infected machine to contact a server on the web to download another program that lets it be taken over remotely by an attacker.

The partner server that held the remote control code has now been shut down.

Oliver Friedrichs, senior manager with Symantec Security Response, said that he expected future versions of the bug to strike when images are viewed with the Internet Explorer browser and Outlook.

Microsoft played down the threat from the images. In a statement it said few people were likely to fall victim because of the series of steps they had to go through to get infected.

The net watchdog, the Internet Storm Center, said the poisoned images only crashed computers in tests, but added that working versions were probably close to being finished.

It also said that poisoned images were starting to circulate on AOL Instant Messenger.

Security firm F-Secure said that, so far, the few poisoned pictures posted on Usenet were not a virus because they do not replicate.

"Unfortunately I have a nasty feeling we might sooner or later see a mass-mailer worm using a Jpeg image as the attachment," wrote Mikko Hypponen in the company's online journal.

Users who have updated their Windows XP machines with the SP2 update could still be at risk from this bug if they are running unpatched programs, such as Microsoft Office, that are vulnerable.

Microsoft is urging people to update their version of Windows and download patches to close the loophole.

Some security firms have also produced tools that let users scan computers to see which machines are vulnerable to the exploit.

Anti-virus firms have updated their software to recognise the signature of the virus-bearing images.

http://news.bbc.co.uk/1/hi/technology/3701640.stm