An app that purportedly spoofed a Mac so that Android smartphone and tablet owners could send and receive text-like messages through Apple’s iMessage service disappeared this week from the Google Play app store.
Google confirmed that it yanked the app for violating its store policies.
Dubbed ‘iMessage Chat’, the app came under quick fire on Monday from other app developers who said the program may have been harvesting Apple ID usernames and passwords by passing packets through a China-based server.
The app first appeared on Google Play on 12 September and was available as late as Monday. By the following day, however, it had been scrubbed from the app store.
iMessage is Apple’s proprietary technology that is embedded in the Message apps for iOS 5 and later and OS X Mountain Lion. When users text another iOS device or a Mac, they sidestep their mobile carrier’s traditional SMS (short message service), avoiding texting charges.
The Android app was designed to let users piggyback on Apple’s iMessage service to send and receive texts.
But concerns about the implications quickly surfaced.
“iMessage for Android app has code to download APKs in the background? TOTALLY SAFE. Not rootkit-ing your phone or anything? ,” tweeted Steve Troughton-Smith, an app developer with High Caffeine Content, on Monday.
The term ‘APK’ in Troughton-Smith’s tweet referred to the file format used by Android to install apps and other code on the operating system.
Others pointed out that users of the app were required to log in using their Apple ID username and password, and that the developer may have simply built the program to collect those valuable credentials, which are used to access iOS devices remotely for data wiping, purchasing content on iTunes and buying goods, including iPhones and Macs, through Apple’s online store.
Jay Freeman, who goes by the online nickname ‘saurik’, dug inside the app and tracked the packets it sent and received. Freeman is best known as the developer of Cydia, the open-source application installer that acts as an App Store substitute for jailbroken iPhones.
He found that iMessage Chat for Android essentially inserted itself into the middle of the normal back-and-forth between a user and Apple’s iMessage servers. In a thread on Hacker News, Freeman spelled out his findings.
“I believe that this application actually does connect to Apple’s servers from the phone, but it doesn’t then interpret the protocol on the device,” Freeman wrote on the thread. “Instead, it ferries the data to the third-party developer’s server, parses everything remotely, figures out what to do with the data, and sends everything back to the client decoded along with responses to send back to Apple.”
Commenters on Freeman’s Google+ page, where he also discussed iMessage Chat, pointed out the danger of trusting a third-party app with an Apple ID. “Seems to be a quick way to get pwnd in some way or another,” said Hugo Visser, a Dutch developer of Android apps.
Commenters also noted that the China-based server was running SQL Server, which was accessible from the internet, posing yet another threat to anyone who used iMessage Chat. Even if the developer was on the up-and-up, and wasn’t harvesting Apple IDs, the server could be hacked by others, who would then be able to sweep up the credentials.
Someone who identified themselves as ‘Hu LuWa’ – the name used for the developer’s website, according to Google Play – dropped in on Freeman’s Google+ page to post one comment, but did not answer any of the several questions others posed.
The developer’s website – huluwa.org – was offline by the middle of the week. A message left on a Google+ page assigned to Hu LuWa was not returned.
A Google spokeswoman confirmed the company had pulled the app. “We remove apps from Google Play that violate our policies,” she wrote in an email reply to questions.
by Gregg Keizer, Computerworld