A modern Android powered smartphone is a complex hardware device: Android OS runs on a multi-core CPU – also called an Application Processor (AP). And the AP is one of many such processors of a System On Chip (SoC). Other processors on the SoC perform various specialized tasks — such as security functions, image & video processing, and most importantly cellular communications. The processor performing cellular communications is often referred to as the baseband. For the purposes of this blog, we refer to the software that runs on all these other processors as “Firmware”.
Securing the Android Platform requires going beyond the confines of the Application Processor (AP). Android’s defense-in-depth strategy also applies to the firmware running on bare-metal environments in these microcontrollers, as they are a critical part of the attack surface of a device.
A popular attack vector within the security research community
As the security of the Android Platform has been steadily improved, some security researchers have shifted their focus towards other parts of the software stack, including firmware. Over the last decade there have been numerous publications, talks, Pwn2Own contest winners, and CVEs targeting exploitation of vulnerabilities in firmware running in these secondary processors. Bugs remotely exploitable over the air (eg. WiFi and cellular baseband bugs) are of particular concern and, therefore, are popular within the security research community. These types of bugs even have their own categorization in well known 3rd party exploit marketplaces.
Regardless of whether it is remote code execution within the WiFi SoC or within the cellular baseband, a This article has been indexed from Google Online Security Blog