CVE-2017-5947 in OxygenOS
Summary
by MITRE
An issue was discovered in OnePlus One, X, 2, 3, 3T, and 5 devices with OxygenOS 5.0 and earlier. The attacker can reboot the device into the Qualcomm Emergency Download (EDL) mode through ADB or by using Volume-Up when connected to USB, which in turn could allow for downgrading partitions such as the Android Bootloader.
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Analysis
by VulDB Data Team • 01/18/2020
This vulnerability exists in OnePlus devices running OxygenOS 5.0 and earlier versions, representing a critical security flaw in the device's boot process and firmware protection mechanisms. The issue stems from insufficient validation of boot mode transitions and inadequate protection against unauthorized access to the Qualcomm Emergency Download mode. Attackers can exploit this weakness by leveraging ADB (Android Debug Bridge) commands or by physically interacting with the device through the volume up button while connected via USB cable. This creates a persistent attack vector that bypasses normal security controls and allows for unauthorized system manipulation.
The technical implementation of this vulnerability involves the improper handling of USB connection events and ADB commands that should normally be restricted to authorized users. When an attacker connects their device to a computer and either uses ADB commands or presses the volume up button during USB connection, the device fails to properly validate the request and transitions into Qualcomm EDL mode. This mode is typically intended for authorized firmware updates and device recovery operations, but the vulnerability allows for its invocation without proper authentication or authorization checks. The flaw specifically affects devices with Qualcomm Snapdragon processors and demonstrates weaknesses in the device's secure boot implementation and USB interaction protocols.
The operational impact of this vulnerability is severe as it enables attackers to perform unauthorized firmware downgrades and potentially install malicious bootloader versions. Once in EDL mode, attackers can manipulate critical system partitions including the Android Bootloader, which serves as the foundation for the entire operating system. This capability allows for complete system compromise and persistent access, as the attacker can install custom firmware that maintains persistence across device reboots. The vulnerability essentially provides a backdoor access mechanism that bypasses normal security boundaries and could enable full device compromise. This aligns with CWE-284, which describes inadequate access control in software implementations, and represents a significant violation of the principle of least privilege in device security architecture.
The attack surface for this vulnerability is particularly concerning as it requires minimal technical expertise and can be executed through simple physical interaction or basic ADB commands. The attack chain begins with physical device connection or ADB access, followed by triggering the specific USB interaction pattern, and concludes with unauthorized bootloader manipulation. This vulnerability demonstrates the critical importance of secure boot processes and proper USB interaction handling in mobile devices. Organizations should implement mitigations including firmware updates to address the vulnerability, disabling ADB in production environments, and implementing proper device authentication mechanisms. The flaw also highlights the need for robust physical security controls and the importance of following secure development practices that incorporate proper access control validation at all system entry points. This vulnerability has been addressed in subsequent firmware updates and serves as a reminder of the critical security considerations in mobile device boot processes and the importance of maintaining secure firmware update mechanisms.