CVE-2017-5626 in OxygenOS
Summary
by MITRE
OxygenOS before version 4.0.2, on OnePlus 3 and 3T, has two hidden fastboot oem commands (4F500301 and 4F500302) that allow the attacker to lock/unlock the bootloader, disregarding the 'OEM Unlocking' checkbox, without user confirmation and without a factory reset. This allows for persistent code execution with high privileges (kernel/root) with complete access to user data.
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Analysis
by VulDB Data Team • 09/06/2020
The vulnerability identified as CVE-2017-5626 represents a critical security flaw in OxygenOS versions prior to 4.0.2 affecting OnePlus 3 and 3T devices. This issue stems from the presence of two undocumented fastboot oem commands with hexadecimal identifiers 4F500301 and 4F500302 that bypass the standard security mechanisms designed to protect bootloader integrity. The flaw operates at the firmware level, specifically within the fastboot interface that is typically used for device flashing and recovery operations. These hidden commands allow unauthorized modification of the device's bootloader state without the typical user confirmation prompts that should be required for such critical operations.
The technical implementation of this vulnerability involves the exploitation of a design oversight in the fastboot protocol implementation within the OxygenOS firmware. The 4F500301 and 4F500302 commands function as direct kernel-level interfaces that can manipulate the bootloader lock status regardless of the OEM Unlocking setting configured by the user. This bypass mechanism operates at a level below the standard Android security model, effectively circumventing the user authentication requirements that should normally be enforced during bootloader modification processes. The vulnerability is particularly concerning because it does not require a factory reset or any form of user interaction beyond the initial command execution, making it highly persistent and difficult to detect.
The operational impact of CVE-2017-5626 extends far beyond simple bootloader manipulation, providing attackers with complete system compromise capabilities. Once the bootloader is unlocked through these hidden commands, adversaries can execute arbitrary code with kernel-level privileges, effectively achieving root access to the device. This level of access enables complete data exfiltration, persistent backdoor installation, and the ability to modify system files without any detection mechanisms. The vulnerability creates a persistent threat vector that remains active even after device reboots, as the bootloader state is modified at the firmware level rather than in volatile memory. From a cybersecurity perspective, this vulnerability represents a significant bypass of the Android security model's principle of least privilege and user consent requirements.
Security researchers have classified this vulnerability under CWE-284, which addresses improper access control, specifically focusing on inadequate privileges for critical system operations. The flaw also aligns with ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation" and demonstrates how attackers can leverage undocumented system interfaces to achieve elevated privileges. The vulnerability's persistence nature makes it particularly dangerous as it can be exploited repeatedly without requiring additional user interaction or device-specific conditions. Organizations and individuals should recognize this as a critical security issue that requires immediate attention through firmware updates and security configuration reviews. The presence of such hidden commands in production firmware also raises concerns about the overall security testing and code review processes employed by the vendor, potentially indicating broader security architecture weaknesses that could affect other device functionalities.