Original URL: http://www.theregister.co.uk/2012/05/21/zte_android_smartphone_backdoor/

Backdoor sniffed in ZTE's US Android smartphones

Dial R for Root

By John Leyden

Posted in Security, 21st May 2012 19:04 GMT

Chinese handset manufacturer ZTE has confirmed the presence of a backdoor in one of its Android smartphones.

ZTE's Score M ships with an application featuring a hardcoded password that gives the user, or software running on the device, administrator-level access. Running the program with the password spawns a root shell prompt on the Linux-powered mobes, allowing the phone to be completely taken over.

News of the ZTE Score M smartphone backdoor first surfaced last week in posts on the code-sharing website pastebin.com. The password needed to access the backdoor, located in the /system/bin/sync_agent file, is readily available online.

The world's fourth largest mobe-maker acknowledged a problem, but said it was restricted to the Score M, which runs Android 2.3.4 and is distributed through MetroPCS in the US. ZTE is working on an "over the air" patch to close the security hole, and the handset manufacturer insists that the issue does not affect Skate smartphones - contrary to internet rumours.

Mobile security firm Lookout advises users of the model to be particularly careful about apps they download and websites they visit until they get the security patch from ZTE. The poorly protected setuid executable on the smartphones allows an application to grant itself superuser privileges and run as the root user, Lookout explains.

"This type of access allows an attacker full control over a target device – which includes the ability to install or uninstall applications without notice and access to any sensitive personal information on a device," Lookout warns.

"While this issue does not expose a remotely accessible vulnerability on affected phones, it is an issue that could be exploited by targeted, malicious applications installed to the phone. In addition, affected users should download and install patches provided by ZTE and/or Metro PCS as soon as they are rolled out to their device," it adds.

The sync_agent tool might have been put there to manage preloaded applications, such as MetroPCS Visual Voicemail or MetroStudio, according to Lookout.

Dmitri Alperovitch, co-founder of security startup CrowdStrike, said ZTE was using the backdoor to update the smartphone's software, suggesting that the feature was placed there deliberately. However he said that it was unclear to him if the application was planted with malicious intent or left available as the result of some careless oversight, Reuters reports.

"There are rumours about backdoors in Chinese equipment floating around," Alperovitch said. "That's why it's so shocking to see it blatantly on a device."

The circumstances of the problem, especially the fact that the problem was restricted to smartphones supplied to the US, is bound to provide plenty of fodder for conspiracy theorists. China is repeatedly accused of using technology to spy on the West's high-tech biz, defence contractors, human right activists and energy firms. Allegations of backdoors in devices supplied by Chinese network equipment manufacturers have been a hot topic among Western politicians. ®