CVE-2019-16243 in Cingular Flip 2 B9HUAH1
Summary
by MITRE
On TCL Alcatel Cingular Flip 2 B9HUAH1 devices, there is an undocumented web API that allows unprivileged JavaScript, including JavaScript running within the KaiOS browser, to view and edit the device's firmware over-the-air update settings. (This web API is normally used by the system application to trigger firmware updates via OmaService.js.)
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Analysis
by VulDB Data Team • 08/30/2020
This vulnerability exists within the TCL Alcatel Cingular Flip 2 B9HUAH1 mobile device firmware, specifically targeting the Over-The-Air (OTA) update configuration management system. The flaw represents a critical security oversight where an undocumented web application programming interface provides unauthorized access to firmware update settings through client-side JavaScript execution. The vulnerability is particularly concerning because it allows unprivileged JavaScript code, including scripts running within the KaiOS browser environment, to manipulate sensitive system configurations that should be restricted to system-level applications only.
The technical implementation of this vulnerability stems from the improper exposure of internal system APIs that are typically restricted to trusted system applications. The web API in question was originally designed to facilitate firmware updates through the OmaService.js component, but the lack of proper access controls means that any JavaScript code executing within the browser context can invoke these functions. This creates a privilege escalation scenario where user-space JavaScript can directly interact with system-level firmware management functions, effectively bypassing normal security boundaries that should separate user applications from critical system operations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables full manipulation of the device's firmware update behavior. An attacker could potentially disable automatic updates, modify update schedules, or even trigger malicious firmware installations that could compromise the device's integrity. The vulnerability is particularly dangerous in environments where these devices are deployed in sensitive locations or where they handle confidential data, as it could be exploited to create persistent backdoors or prevent security patches from being applied. This makes the device susceptible to various attack vectors including firmware downgrade attacks, malicious update injection, and complete device compromise through unauthorized firmware modifications.
This vulnerability aligns with CWE-284 (Improper Access Control) and represents a clear violation of the principle of least privilege in system design. The exposure of system-level functionality to unprivileged JavaScript execution directly contradicts standard security practices and creates a significant attack surface for threat actors. From an ATT&CK framework perspective, this vulnerability maps to multiple techniques including T1059.007 (Command and Scripting Interpreter: JavaScript) and T1068 (Exploitation for Privilege Escalation) while also enabling potential lateral movement through compromised device firmware. The vulnerability demonstrates a critical failure in the device's security architecture where proper API access controls were not implemented, allowing arbitrary JavaScript execution to gain elevated privileges.
Mitigation strategies should focus on implementing proper access controls and authentication mechanisms for all system APIs, particularly those related to firmware management and device configuration. Device manufacturers should conduct comprehensive security reviews of all exposed interfaces and ensure that only authorized system applications can invoke critical functions through proper API gateways with appropriate authentication and authorization checks. Additionally, the firmware should be updated to remove or secure the undocumented API, and proper input validation should be implemented to prevent unauthorized access to system-level functions. Regular security assessments should be performed to identify and remediate similar vulnerabilities in other device components, ensuring that all system interfaces adhere to established security standards and minimize attack surface exposure.