Cookie handling in browsers can break HTTPS security

The lack of cookie integrity verification in browsers can allow hackers to extract information from encrypted Web connections.

Cookies, the files that websites create in browsers to remember logged-in users and track other information about them, could be abused by attackers to extract sensitive information from encrypted HTTPS connections.

The issue stems from the fact that the HTTP State Management standard, or RFC 6265, which defines how cookies should be created and handled, does not specify any mechanism for isolating them or checking their integrity.

As such, Web browsers don't always authenticate the domains that set cookies. That allows malicious attackers to inject cookies via plain HTTP connections that would later be transmitted for HTTPS connections instead of those set by the HTTPS sites themselves, the CERT Coordination Center (CERT/CC) at Carnegie Mellon University said in an advisory Thursday.

One of the reasons why this happens is because subdomains can set cookies that are valid for their parent domains or other subdomains.

For example, if subdomain.domain.com sets a cookie with the domain attribute of domain.com, that cookie might be sent by the browser to subdomain2.domain.com as well. The site hosted on subdomain2 might not be able to differentiate between its own cookie and the rogue one.

Cookies are also not isolated by port number or scheme. A server can host multiple websites accessible via the same domain, but on different port numbers. Those websites will be able to read and write each other's cookies.

All these inconsistencies can allow man-in-the-middle attackers to perform so-called cookie injection or cookie tossing attacks that can be used to extract sensitive information from HTTPS connections.

A team of researchers from University of California, Berkeley, Tsinghua University in Beijing, the International Computer Science Institute and Microsoft tested the implications of such attacks on different high-profile HTTPS websites and presented their findings in August at the USENIX conference.

They found that they could hijack users' chat gadgets in the Gmail interface, steal Google search histories, steal credit card information on China UnionPay's website, hijack deposits on JD.com, hijack Google OAuth and BitBucket associations, track and manipulate shopping carts on e-commerce sites, track purchase history on Amazon.com and more.

"Some web browser vendors have noted previous attempts at more secure cookie management have been foiled due to the lack of a widely implemented standard," the CERT/CC said in its advisory.

Until the standards bodies come up with a solution, the issue can be mitigated if websites use the HTTP Strict Transport Security (HSTS) mechanism to force browsers to always access them over secure HTTPS connections.

The latest versions of all major browsers support HSTS, but in order for this mechanism to be effective against cookie injection attacks, websites also need to implement it.

Unfortunately, HSTS adoption across HTTPS-enabled websites remains low. According to the latest statistics from the SSL Pulse project, only 4.5 percent of the Internet's top 145,000 HTTPS websites currently support HSTS.

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection
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

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Kurt Hegetschweiler

Brother PocketJet PJ-773 A4 Portable Thermal Printer

It’s perfect for mobile workers. Just take it out — it’s small enough to sit anywhere — turn it on, load a sheet of paper, and start printing.

Matthew Stivala

HP OfficeJet 250 Mobile Printer

The HP OfficeJet 250 Mobile Printer is a great device that fits perfectly into my fast paced and mobile lifestyle. My first impression of the printer itself was how incredibly compact and sleek the device was.

Armand Abogado

HP OfficeJet 250 Mobile Printer

Wireless printing from my iPhone was also a handy feature, the whole experience was quick and seamless with no setup requirements - accessed through the default iOS printing menu options.

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.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?