CVE-2017-2691 in Huawei
Summary
by MITRE
Huawei P9 versions earlier before EVA-AL10C00B373, versions earlier before EVA-CL00C92B373, versions earlier before EVA-DL00C17B373, versions earlier before EVA-TL00C01B373 have a lock-screen bypass vulnerability. An unauthenticated attacker could force the phone to the fastboot mode and delete the user's password file during the reboot process, then login the phone without screen lock password after reboot.
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Analysis
by VulDB Data Team • 01/11/2023
This vulnerability resides in Huawei P9 mobile devices running specific firmware versions prior to EVA-AL10C00B373, EVA-CL00C92B373, EVA-DL00C17B373, and EVA-TL00C01B373, representing a critical security flaw in the device's lock-screen protection mechanism. The vulnerability stems from improper handling of the device reboot process within the fastboot mode, creating an exploitable condition that allows unauthorized access to the device without proper authentication. This weakness specifically affects the Android-based operating system implementation on these Huawei devices, where the security boundary between the fastboot mode and the normal boot process has been compromised.
The technical exploitation of this vulnerability involves an unauthenticated attacker leveraging a specific sequence of device operations to force the phone into fastboot mode during a normal reboot cycle. Once in this mode, the attacker can manipulate the device's boot process to delete or overwrite the password file that stores the screen lock credentials. This manipulation occurs during the critical boot phase when the device transitions from fastboot mode back to normal operating mode, creating a window where the system's authentication mechanisms are temporarily bypassed. The vulnerability essentially represents a race condition or timing flaw in the device's boot sequence, where the security checks fail to properly validate the integrity of the authentication files during the reboot process.
The operational impact of this vulnerability is severe as it completely undermines the device's primary security feature - the screen lock mechanism. An attacker with physical access to an unattended device can gain full access to all stored data, applications, and personal information without requiring any authentication credentials. This vulnerability affects not only the device's immediate security but also creates potential for broader data breaches, as users may store sensitive information including personal documents, financial data, communication records, and corporate information on these devices. The vulnerability is particularly concerning in enterprise environments where employees may use these devices for work-related activities, potentially exposing sensitive corporate data to unauthorized access.
This vulnerability maps directly to CWE-284: Improper Access Control, specifically addressing insufficient access control mechanisms within the device's boot and authentication processes. The flaw also aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation, as the attacker can escalate their privileges from unauthenticated access to full device control. Additionally, the vulnerability demonstrates characteristics of T1072: Software Deployment Tools, as it exploits the device's legitimate software deployment mechanisms to gain unauthorized access. The exploitation requires physical access to the device but does not require advanced technical skills beyond understanding the device's boot process, making it particularly dangerous in scenarios where devices are left unattended in public or shared environments.
Mitigation strategies for this vulnerability primarily involve updating the device firmware to the patched versions mentioned in the CVE description. Huawei should implement proper authentication checks during the fastboot mode transition and ensure that the password file integrity is maintained throughout the reboot process. Device manufacturers should also consider implementing additional security measures such as secure boot mechanisms, integrity checks for critical system files, and enhanced access control validation during device transitions. Users should be advised to keep their devices updated with the latest security patches and to avoid leaving devices unattended in public places. Organizations should implement device management policies that enforce regular security updates and monitor for vulnerable device populations within their enterprise networks. The vulnerability highlights the importance of proper boot process security and the need for robust access control mechanisms even in the most critical system transitions.