CVE-2016-4032 in Galaxy S4
Summary
by MITRE
Samsung SM-G920F build G920FXXU2COH2 (Galaxy S6), SM-N9005 build N9005XXUGBOK6 (Galaxy Note 3), GT-I9192 build I9192XXUBNB1 (Galaxy S4 mini), GT-I9195 build I9195XXUCOL1 (Galaxy S4 mini LTE), and GT-I9505 build I9505XXUHOJ2 (Galaxy S4) devices do not block AT+USBDEBUG and AT+WIFIVALUE, which allows attackers to modify Android settings by leveraging AT access, aka SVE-2016-5301.
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Analysis
by VulDB Data Team • 08/30/2020
The vulnerability identified as CVE-2016-4032 represents a critical security flaw in several Samsung Android devices including the Galaxy S6, Galaxy Note 3, and various Galaxy S4 models. This weakness stems from the improper handling of AT command interfaces that are typically used for modem communication and device configuration. The vulnerability allows unauthorized modification of Android system settings through direct access to AT command channels, creating a significant attack surface that bypasses normal Android security mechanisms. The affected devices operate with specific build versions that contain this flaw, making them susceptible to exploitation by attackers who can leverage these AT command interfaces to gain elevated privileges and modify critical system parameters.
The technical root cause of this vulnerability lies in the insufficient validation and access control mechanisms implemented for AT command processing within the Android framework of these mobile devices. Specifically, the AT+USBDEBUG and AT+WIFIVALUE commands are not properly restricted or validated, allowing malicious actors to execute these commands without proper authentication or authorization. This represents a classic case of inadequate input validation and privilege escalation, where the system fails to properly verify the legitimacy of AT command requests. The vulnerability is classified under CWE-284, which deals with improper access control, and demonstrates how insecure command interfaces can provide attackers with direct pathways to system modification capabilities. The flaw essentially allows attackers to manipulate device behavior through direct hardware-level commands that should normally be restricted to authorized system processes.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to modify critical Android settings that can compromise device security and functionality. Through the exploitation of these AT command interfaces, adversaries can potentially enable USB debugging, modify wireless configurations, and alter other system parameters that affect device integrity and user privacy. This vulnerability creates a persistent threat vector that can be exploited remotely or through physical access, depending on the attack scenario. The implications align with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries use legitimate system interfaces to execute malicious commands. The vulnerability affects multiple device generations and model numbers, indicating a widespread issue that requires comprehensive remediation across Samsung's product portfolio.
Mitigation strategies for this vulnerability should focus on implementing proper access controls and input validation for AT command interfaces within the Android operating system. Device manufacturers should ensure that all AT commands are properly authenticated and authorized before execution, with appropriate privilege checks and validation mechanisms in place. System updates and patches should be deployed immediately to address this flaw, as the vulnerability can be exploited without user interaction and provides attackers with direct system modification capabilities. Security configurations should include disabling unnecessary AT command interfaces when they are not actively required for device operation, and implementing monitoring mechanisms to detect unauthorized AT command usage. Organizations should also consider network-level controls to prevent unauthorized access to device interfaces and implement comprehensive security awareness training for personnel who may interact with these devices. The vulnerability highlights the importance of secure coding practices and proper privilege management in mobile operating systems, particularly in areas where low-level hardware interfaces are exposed to application-level processes.