Google Issuing Fix For Latest Android Vulnerability Disclosure

Google has been issuing updates since last week to its Android platform to fix one of two recently revealed vulnerabilities that could allow an attacker to install applications on a phone without the explicit permission of the smartphone user.

Researchers last week at Black Hat Abu Dhabi and at Intel's annual internal security conference, held in Oregon, separately demonstrated two different vulnerabilities in the Android that each leave the door wide open for an attacker to force a malicious app onto the smartphone, bypassing user permissions prompt.

Jon Oberheide, CTO of Scio Security, along with Zach Lanier, senior consultant at Intrepidus Group, at the Intel conference demonstrated how a vulnerability in the Android platform let them use a phony add-on for a real gaming app to sneak three additional malicious apps onto the phone. "Our proof-of-concept was an app that pretended to be an Angry Birds bonus levels [free app]" in the Android Marketplace, Oberheide says. Then in the background, the researchers also installed a fake toll fraud, fake contact-stealer, and fake location tracker app.

It's Oberheide and Lanier's vulnerability that Google, which pulled the app last week, is now fixing. Google last week also yanked the researchers' phony app from the Android Market. "We've begun rolling out a fix for this issue, which will apply to all Android devices. As always, we advise users to only install applications they trust," a Google spokesperson said.

Meanwhile, the vulnerability demonstrated at Black Hat Abu Dhabi by researcher Nils, head of research for MWR InfoSecurity, is actually in the HTC smartphone's implementation of Android. The flaw was introduced via a setting provided by HTC. Nils says he tried to contact HTC about the flaw, but has not received any response.

Nils' attack worked against an HTC Legend running Android 2.1 and can be waged using a browser exploit. The attack basically updated components of the browser without alerting the user via the user permissions function. Neither Oberheide and Lanier's nor Nils' attacks go after the Linux kernel, but rather the user space of the smartphone.

"In our [PoC], there would be some notification to the user in the top bar showing the app was being installed. You might think that's a negative thing from an attacker's standpoint because it's notifying the user that something is being installed. But in reality ... if the user clicks on it, it will launch the app," Oberheide says.

It has been a rough year for Android security-wise. Researchers have been hammering away at the increasingly popular open-source smartphone platform, and a recent study said Google's popular Android mobile platform kernel contains more than 350 software flaws, one-fourth of which are high-risk for security breaches and system crashes.

But the underlying issue is similar to that of the desktop world, says Kevin Mahaffey, CTO at Lookout Security, a mobile security provider. "This harkens back to the PC world. Vulnerabilities can be introduced in any form at any part of the [software] chain," Mahaffey says. And Android is more at risk of a third-party introducing vulnerabilities at the system level than RIM's BlackBerry or Apple's iPhone, both of which are more under the control of the vendors, he says.

Patching smartphones is not so simple, either, he says. "If there's a long pipeline, the app vendor has to get the patches to acceptable quality ... especially if you have an OS [separate] from the platform device manufacturer," Mahaffey says. "Patching is slower than on a PC."

Meanwhile, Oberheide says his and Lanier's PoC works by getting the Google service to trigger the installation mechanism. "You see a legit app installation request -- the same installation request a legitimate Market app would send to the Google service to trigger this installation mechanism," he says.

He says the Android app market doesn't vet apps enough. Still, most attacks on smartphones thus far have been pretty basic, he says. "There's been the low-hanging fruit of fraud, such as SMS fraud, and a lot of app fraud," Oberheide says. But even the app fraud seen so far is more about making money than stealing information, such as with a phony New York Times app sold for 99 cents that only displays the website to the Times, he notes.

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