Web browser attack skirts corporate firewall

A 10-year-old security problem has come back to haunt corporate IT, a security researcher told an audience at the Black Hat conference in Las Vegas Wednesday.

A 10-year-old security problem has come back to haunt corporate IT, a security researcher told an audience at the Black Hat conference in Las Vegas Wednesday.

Dan Kaminsky, director of penetration testing for IO Active, showed how problems in the way browser software works with the Internet's domain name system could be exploited to give attackers access to any resources behind the corporate firewall.

He described a multi-step attack that could be used to scan corporate networks for data or vulnerabilities. But at the heart of the attack is a 1996 paper by Princeton researchers showing how a Java applet could be used to access systems on a victim's network. "It's one of the few things that's actually come back from the dead," Kaminsky said.

The fundamental problem, according to Kaminsky, is in the way that Web browser software decides how to trust other computers. This decision is based on the Internet domain name of the computer, and that DNS (Domain Name System) information can be misused, Kaminsky said. "It's a binding problem," he said during an interview after his talk. "They assume a value is not changing, but the attacker can change it whenever he chooses."

For the past year, security researchers like Kaminsky have increasingly warned how flaws in the security model of Internet applications could be misused to give attackers access to PC resources or other Web sites being visited by the victim.

In February, security researcher Robert Hansen showed how a DNS-based attack called "anti-DNS pinning" could be used to give an attacker access to any data indexed by Google Desktop.

Hansen said that while Kaminsky's talk may not have disclosed previously unknown vulnerabilities, "it's probably one of the coolest implementations" of this type of attack.

In his talk, Kaminsky described how a malicious Web site could interact with a browser and -- following a complex chain of back-and-forth data requests -- ultimately gain access to other resources on the Web surfer's network. Attackers would be able to access any resource available to the victim running the browser, he said. "If you can reach it, so can the bad guy."

He plans to post further details of his attack on his Doxpara.com Web site later this week.

In Kaminsky's scenario, an attacker would use a proxy server that would send data to the browser, ultimately using Adobe Systems's Flash multimedia software to trick the browser into trusting the outside Web site as if it was a local network resource, say a printer. "The proxy gets to update the browser to speak the necessary flash to service the bytes being sent to the attacker," he said.

Join the PC World newsletter!

Error: Please check your email address.

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.

Robert McMillan

IDG News Service
Show Comments

Essentials

Lexar® JumpDrive® S57 USB 3.0 flash drive

Learn more >

Microsoft L5V-00027 Sculpt Ergonomic Keyboard Desktop

Learn more >

Mobile

Lexar® JumpDrive® S45 USB 3.0 flash drive 

Learn more >

Exec

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

Learn more >

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

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

Learn more >

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

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?