A team of six researchers from Indiana University, Georgia Tech and Peking University have published an in-depth report exposing a series of security vulnerabilities that enable sandboxed malicious apps, approved on the App Store, to gain unauthorized access to sensitive data stored in other apps, including iCloud passwords and authentication tokens, Google Chrome saved web passwords and more.

"We completely cracked the keychain service - used to store passwords and other credentials for different Apple apps - and sandbox containers on OS X, and also identified new weaknesses within the inter-app communication mechanisms on OS X and iOS which can be used to steal confidential data from Evernote, Facebook and other high-profile apps."

The thirteen-page research paper "Unauthorized Cross-App Resource Access on Mac OS X and iOS" details that inter-app interaction services, ranging from the Keychain and WebSocket on OS X to the URL Scheme on OS X and iOS, can be exploited to steal confidential information and passwords, including those stored in popular password vaults such as 1Password by AgileBits.

The different cross-app and communication mechanism vulnerabilities discovered on iOS and OS X, identified as XARA weaknesses, include Keychain password stealing, IPC interception, scheme hijacking and container cracking. The affected apps and services include iCloud, Gmail, Google Drive, Facebook, Twitter, Chrome, 1Password, Evernote, Pushbullet, Dropbox, Instagram, WhatsApp, Pinterest, Dashlane, AnyDo, Pocket and several others.

Lead researcher Luyi Xing told The Register that he reported the security flaws to Apple in October 2014 and complied with the iPhone maker's request to withhold publishing the information for six months, but has not heard back from the company since and is now exposing the zero-day vulnerabilities to the public. The flaws affect thousands of OS X apps and hundreds of iOS apps and can now be weaponized by attackers.