PayPal is the latest victim of Java deserialization bugs in Web apps

The company's Java-based, back-end system was vulnerable to an attack that researchers have warned about for a year

PayPal has fixed a serious vulnerability in its back-end management system that could have allowed attackers to execute arbitrary commands on the server and potentially install a backdoor.

The vulnerability is part of a class of bugs that stem from Java object deserialization and which security researchers have warned about a year ago.

In programming languages, serialization is the process of converting data to a binary format for storing it or for sending it over the network. Deserialization is the reverse of that process.

Deserialization is not an issue in itself, but like most processes that involve processing potentially untrusted input, measures need to be taken to ensure that it is performed safely. For example, an attacker could craft a serialized object that includes a Java class that the application accepts and which could be abused for something malicious.

Security researchers Chris Frohoff and Gabriel Lawrence gave a presentation about  this type of attack at a security conference a year ago. Then in November, researchers from a company called FoxGlove Security published a proof-of-concept exploit for a deserialization vulnerability in a popular library called Apache Commons Collections that's included by default on many Java application servers.

Security researchers warned at the time that thousands of Java-based Web applications, including custom-made enterprise ones, are likely vulnerable to this attack and said that both good and bad hackers will likely start probing for it.

Michael Stepankin, the bug bounty hunter who found the recent vulnerability in the manager.paypal.com website, is one such hacker. He was inspired by the research from Frohoff, Lawrence and the FoxGlove researchers and even used one of the tools they produced to build his attack payload.

After determining that the PayPal site was vulnerable to Java deserialization, Stepankin was able to exploit the flaw in order to execute arbitrary commands on its underlying Web server.

"Moreover, I could establish a back connection to my own Internet server and, for example, upload and execute a backdoor," he said in a blog post. "In result, I could get access to production databases used by the manager.paypal.com application."

After he reported the issue to PayPal and it got fixed, the company gave him a reward through its bug bounty program, even though his report was marked as a duplicate. It turns out that another security researcher reported the same issue a few days earlier, proving that people are currently scanning for this type of vulnerability.

Developers should make sure that they update the Apache Commons Collections library used by their Java servers and apps to at least versions 3.2.2 or 4.1, which address this issue. However, it's likely that this type of vulnerability exists in other libraries as well, waiting to be discovered.

Join the Good Gear Guide 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.

Lucian Constantin

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?