CVE-2016-3931 in Android
Summary
by MITRE
drivers/misc/qseecom.c in the Qualcomm QSEE Communicator driver in Android before 2016-10-05 on Nexus 5X, Nexus 6, Nexus 6P, and Android One devices allows attackers to gain privileges via a crafted application, aka Android internal bug 29157595 and Qualcomm internal bug CR 1036418.
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Analysis
by VulDB Data Team • 09/22/2022
The vulnerability described in CVE-2016-3931 represents a critical privilege escalation flaw within the Qualcomm QSEE Communicator driver component of Android operating systems. This issue affects specific Qualcomm Snapdragon-powered devices including the Nexus 5X, Nexus 6, Nexus 6P, and Android One models, with the vulnerability existing in Android versions prior to the 2016-10-05 security patch release. The flaw resides in the drivers/misc/qseecom.c file which serves as the interface between the Android system and Qualcomm's TrustZone security environment. This driver facilitates communication with the Qualcomm Secure Execution Environment and handles sensitive operations related to secure application execution and cryptographic functions. The vulnerability allows malicious applications to escalate their privileges from regular user-level access to system-level privileges, effectively bypassing the Android security model that normally separates trusted system components from untrusted user applications.
The technical root cause of this privilege escalation vulnerability stems from improper input validation and insufficient access control mechanisms within the QSEE communicator driver. Attackers can exploit this flaw by crafting a malicious application that sends specially crafted ioctl commands to the vulnerable driver interface. These commands manipulate the driver's handling of memory operations and kernel space access, allowing the attacker to execute arbitrary code with elevated privileges. The vulnerability specifically relates to how the driver processes user-supplied data without adequate sanitization, creating opportunities for memory corruption and unauthorized privilege elevation. According to CWE classification, this represents a weakness in input validation and improper access control, with potential for code execution and system compromise. The flaw aligns with ATT&CK technique T1068 which involves exploiting legitimate credentials and privileges to gain unauthorized access to system resources.
The operational impact of this vulnerability is severe as it provides attackers with complete system compromise capabilities. Once exploited, malicious applications can access all system resources including encrypted data, cryptographic keys, and sensitive user information stored in the secure environment. The vulnerability affects devices that were widely deployed in enterprise and consumer environments, making the potential attack surface extensive. Organizations relying on these devices for security-sensitive operations face significant risk of data breaches, unauthorized access to corporate networks, and potential lateral movement within their infrastructure. The exploitation requires only a malicious application installation, making it particularly dangerous as users may unknowingly install compromised applications from third-party sources or through social engineering attacks. This vulnerability undermines the fundamental security model of Android devices by allowing unprivileged applications to bypass kernel-level protections and gain system-level control.
Mitigation strategies for CVE-2016-3931 primarily involve applying the security patch released by Google and Qualcomm in their October 2016 update cycle. Device users should immediately install the latest security patches available for their specific Android versions and device models. System administrators should conduct comprehensive vulnerability assessments to identify devices running vulnerable Android versions and ensure timely patch deployment. Organizations should implement application whitelisting policies to prevent installation of untrusted applications, particularly on devices that cannot be immediately patched. Network monitoring should be enhanced to detect unusual privilege escalation activities that may indicate exploitation attempts. Additionally, device manufacturers should implement stricter code review processes for kernel drivers and enhance input validation mechanisms to prevent similar vulnerabilities from emerging in future releases. The vulnerability highlights the importance of secure coding practices in kernel-level drivers and the necessity of thorough security testing before device deployment.