CVE-2018-7939 in G9 Lite
Summary
by MITRE
Huawei smart phones G9 Lite, Honor 5A, Honor 6X, Honor 8 with the versions before VNS-L53C605B120CUSTC605D103, the versions before CAM-L03C605B143CUSTC605D008, the versions before CAM-L21C10B145, the versions before CAM-L21C185B156, the versions before CAM-L21C223B133, the versions before CAM-L21C432B210, the versions before CAM-L21C464B170, the versions before CAM-L21C636B245, the versions before Berlin-L21C10B372, the versions before Berlin-L21C185B363, the versions before Berlin-L21C464B137, the versions before Berlin-L23C605B161, the versions before FRD-L09C10B387, the versions before FRD-L09C185B387, the versions before FRD-L09C432B398, the versions before FRD-L09C636B387, the versions before FRD-L19C10B387, the versions before FRD-L19C432B399, the versions before FRD-L19C636B387 have a Factory Reset Protection (FRP) bypass security vulnerability. When re-configuring the mobile phone using the factory reset protection (FRP) function, an attacker can disable the boot wizard by enable the talkback function. As a result, the FRP function is bypassed.
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Analysis
by VulDB Data Team • 05/16/2023
This vulnerability affects multiple Huawei smartphone models including the G9 Lite, Honor 5A, Honor 6X, and Honor 8 across various firmware versions. The security flaw resides in the Factory Reset Protection (FRP) mechanism that is designed to prevent unauthorized use of devices after a factory reset. The vulnerability allows attackers to bypass this critical security feature by exploiting a specific interaction between the boot wizard and the talkback accessibility function. When an attacker enables the talkback function during the device reconfiguration process, they can effectively disable the boot wizard that normally enforces FRP requirements. This creates a pathway for unauthorized users to circumvent the security protections that should prevent device usage after a factory reset.
The technical implementation of this vulnerability stems from insufficient input validation and improper state management within the device's boot process. The FRP system relies on the boot wizard to enforce security policies during device initialization, but the vulnerability occurs when the talkback function interferes with this process. This represents a classic case of inadequate access control enforcement where the system fails to properly validate user interactions during critical configuration phases. The flaw essentially allows an attacker to manipulate the device's initialization sequence through legitimate accessibility features that should not interfere with security mechanisms.
From an operational impact perspective, this vulnerability significantly undermines the security posture of affected devices by allowing unauthorized access to reset devices without proper authentication. The vulnerability can be exploited by attackers who gain physical access to a device, particularly in scenarios involving stolen or lost devices where the original owner's credentials are not known. This creates a substantial risk for corporate environments where mobile devices contain sensitive data, as attackers can bypass security measures to access corporate resources or personal information. The vulnerability also impacts the device's ability to serve as a secure endpoint, potentially enabling further attacks such as data exfiltration or lateral movement within networks.
The security implications of this vulnerability align with CWE-668 (Exposure of Resource to Wrong Sphere) and CWE-306 (Missing Authentication for Critical Function) as it allows unauthorized access to critical device functions. According to ATT&CK framework, this vulnerability maps to T1490 (Inhibit System Recovery) and T1070 (Indicator Removal on Host) as attackers can bypass security measures and potentially hide their activities. The vulnerability also represents a weakness in the device's integrity verification mechanisms and demonstrates poor separation of concerns between accessibility features and security enforcement components. Organizations should implement immediate mitigations including firmware updates, device enrollment in mobile device management solutions, and enhanced physical security measures for devices in high-risk environments.
The vulnerability highlights the importance of comprehensive security testing during device development, particularly for accessibility features that may interact with security-critical systems. Device manufacturers should implement proper sandboxing and access control mechanisms to prevent legitimate accessibility functions from interfering with security protocols. Additionally, the issue demonstrates the need for regular security assessments of device boot processes and the implementation of robust state management to ensure that critical security checks cannot be bypassed through unintended interactions between system components. This vulnerability serves as a reminder that security controls must be designed with defense-in-depth principles to prevent single points of failure in critical security mechanisms.