Zero-day flaw in Google Admin app allows malicious apps to read its files

Attackers could obtain credentials used to manage Google for Work accounts

Google, Samsung and LG will move to a monthly security patch release for Android devices after a range of software vulnerabilities were recently disclosed.

Google, Samsung and LG will move to a monthly security patch release for Android devices after a range of software vulnerabilities were recently disclosed.

An unpatched vulnerability in the Google Admin application for Android can allow rogue applications to steal credentials that could be used to access Google for Work acccounts.

One of the main aspects of the Android security model is that apps run in their own sandboxes and cannot read each other's sensitive data through the file system. There are APIs for applications to interact with each other and exchange data, but this requires mutual agreement.

But researchers from security consultancy firm MWR InfoSecurity in the U.K. discovered a flaw in the Google Admin app that could be exploited by potentially malicious applications to break into the app's sandbox and read its files.

The flaw lies in the way Google Admin processes and loads URLs received from other applications inside a WebView -- a simplified browser window.

If a rogue application sends Google Admin a request -- or "intent" in Android parlance -- with a URL pointing to a local world-readable HTML file that the rogue app controls, Google Admin will load the file's code in a WebView.

The attacker can put an iframe inside the HTML code that will load the same file again after a one second delay, the MWR researchers explained in an advisory published Thursday. After Google Admin loads the HTML code, but before it attempts to load the iframe, the attacker can replace the original file with one that has the same name but acts as a symbolic link to a file within the Google Admin app, they said.

WebView has a security mechanism called the Same-Origin Policy that is present in all browsers and which prevents a Web page from reading or changing code loaded in an iframe unless both the page and the iframe share the same origin -- domain name and protocol.

Even though the code loaded in the iframe belongs to a Google Admin file, its origin is the same as that of the file from the rogue application thanks to the symlink trick. This means that the original HTML code loaded in the WebView can read the Google Admin file subsequently loaded in the iframe, passing its content to the rogue app.

"The Google Admin app for Android lets the company administrator manage their company's Gmail for Work accounts from his or her Android phone," said Robert Miller, senior security researcher at MWR, via email. "A key file in the Google Admin sandbox is a file holding a token that is used by the app to authenticate itself with the server. A malicious app could exploit the vulnerability found to read this token and attempt to log in to the Google for Work server."

The MWR researchers claim that they reported the vulnerability to Google on March 17, but even after granting the company an extension to the standard 90-day disclosure deadline, it still hasn't been fixed.

"No updated version has been released as of the time of publication," the MWR researchers said in the advisory.

Google did not immediately respond to a request for comment.

Join the newsletter!

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

Tags Googlesecuritymobile securityMWR InfoSecurityExploits / vulnerabilitiesmalware

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

Cool Tech

SanDisk MicroSDXC™ for Nintendo® Switch™

Learn more >

Breitling Superocean Heritage Chronographe 44

Learn more >

Toys for Boys

Family Friendly

Panasonic 4K UHD Blu-Ray Player and Full HD Recorder with Netflix - UBT1GL-K

Learn more >

Stocking Stuffer

Razer DeathAdder Expert Ergonomic Gaming Mouse

Learn more >

Christmas Gift Guide

Click for more ›

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

George Khoury

Sharp PN-40TC1 Huddle Board

The biggest perks for me would be that it comes with easy to use and comprehensive programs that make the collaboration process a whole lot more intuitive and organic

David Coyle

Brother PocketJet PJ-773 A4 Portable Thermal Printer

I rate the printer as a 5 out of 5 stars as it has been able to fit seamlessly into my busy and mobile lifestyle.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?