fastboot oem vuln: Android Bootloader Vulnerabilities in Vendor Customizations

We discuss the fastboot interface of the Android bootloader, an area of fragmentation in Android devices. We then present a variety of vulnerabilities we have found across multiple Android devices. Most notable ones include Secure Boot & Device Locking bypasses in the Motorola and OnePlus 3/3T bootloaders. Another critical flaw in OnePlus 3/3T enables easy attacks by malicious chargers – the only prerequisite is a powered-off device to be connected. An unexpected attack vector in Nexus 9 is also shown – malicious headphones. Other discovered weaknesses allow for data exfiltration (including a memory dumping of a Nexus 5X device), enablement of hidden functionality such as access to the device’s modem diagnostics and AT interfaces , and attacks against internal System-on-Chips (SoCs) found on the Nexus 9 board.