A critical flaw in Symantec antivirus engine puts computers at risk of easy hacking

The flaw could be exploited by simply sending a malicious email or tricking users to visit a link

The antivirus engine used in multiple Symantec products has an easy-to-exploit vulnerability that could allow hackers to easily compromise computers.

The flaw was fixed by Symantec in Anti-Virus Engine (AVE) version 20151.1.1.4, released Monday via LiveUpdate. The flaw consists of a buffer overflow condition that could be triggered when parsing executable files with malformed headers.

According to Google security engineer Tavis Ormandy, who found the flaw, the vulnerability can be exploited remotely to execute malicious code on computers. All it takes is for the attacker to send an email with the exploit file as attachment or to convince the user to visit a malicious link.

Executing the file is not necessary, because the antivirus engine uses a driver to intercept all system input and output operations and will automatically scan the file as soon as it reaches the file system in any way.

The file extension doesn't matter, as long as the file has a header identifying it as a portable executable file packed with ASPack, a commercial compressor utility.

The worst part about it is that the Symantec AVE unpacks such files inside the kernel, the highest privileged region of the OS. This means that successful exploitation can lead to a full system compromise.

"On Linux, Mac and other UNIX platforms, this results in a remote heap overflow as root in the Symantec or Norton process," Ormandy said in an advisory. "On Windows, this results in kernel memory corruption, as the scan engine is loaded into the kernel, making this a remote ring0 memory corruption vulnerability -- this is about as bad as it can possibly get."

Symantec has rated the vulnerability with a 9.1 severity score out of 10 in the Common Vulnerability Scoring System (CVSS).

"The most common symptom of a successful attack would result in an immediate system crash, aka. Blue Screen of Death (BSOD)," the company said in its own advisory.

Users should make sure that they install the latest available updates available for their Symantec antivirus products and can check the version of the AVE using instructions on Symantec's support website.

This is the latest in a long string of critical vulnerabilities found by Ormandy and other security researchers in antivirus products in recent years. Most of them have criticized antivirus vendors for continuing to perform dangerous file scanning operations, which historically have resulted in vulnerabilities, using kernel privileges.

Join the PC World newsletter!

Error: Please check your email address.

Tags securityantivirus

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Lucian Constantin

IDG News Service
Show Comments

Essentials

Microsoft L5V-00027 Sculpt Ergonomic Keyboard Desktop

Learn more >

Lexar® JumpDrive® S57 USB 3.0 flash drive

Learn more >

Mobile

Lexar® JumpDrive® S45 USB 3.0 flash drive 

Learn more >

Exec

Lexar® Professional 1800x microSDHC™/microSDXC™ UHS-II cards 

Learn more >

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

Learn more >

HD Pan/Tilt Wi-Fi Camera with Night Vision NC450

Learn more >

Budget

Back To Business Guide

Click for more ›

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

Azadeh Williams

HP OfficeJet Pro 8730

A smarter way to print for busy small business owners, combining speedy printing with scanning and copying, making it easier to produce high quality documents and images at a touch of a button.

Andrew Grant

HP OfficeJet Pro 8730

I've had a multifunction printer in the office going on 10 years now. It was a neat bit of kit back in the day -- print, copy, scan, fax -- when printing over WiFi felt a bit like magic. It’s seen better days though and an upgrade’s well overdue. This HP OfficeJet Pro 8730 looks like it ticks all the same boxes: print, copy, scan, and fax. (Really? Does anyone fax anything any more? I guess it's good to know the facility’s there, just in case.) Printing over WiFi is more-or- less standard these days.

Ed Dawson

HP OfficeJet Pro 8730

As a freelance writer who is always on the go, I like my technology to be both efficient and effective so I can do my job well. The HP OfficeJet Pro 8730 Inkjet Printer ticks all the boxes in terms of form factor, performance and user interface.

Michael Hargreaves

Windows 10 for Business / Dell XPS 13

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Aysha Strobbe

Windows 10 / HP Spectre x360

Ultimately, I think the Windows 10 environment is excellent for me as it caters for so many different uses. The inclusion of the Xbox app is also great for when you need some downtime too!

Mark Escubio

Windows 10 / Lenovo Yoga 910

For me, the Xbox Play Anywhere is a great new feature as it allows you to play your current Xbox games with higher resolutions and better graphics without forking out extra cash for another copy. Although available titles are still scarce, but I’m sure it will grow in time.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?