CVE-2016-3934 in Android
Summary
by MITRE
drivers/media/platform/msm/camera_v2/sensor/io/msm_camera_cci_i2c.c in the Qualcomm camera driver in Android before 2016-10-05 on Nexus 5, Nexus 5X, Nexus 6, Nexus 6P, and Android One devices relies on variable-length arrays, which allows attackers to gain privileges via a crafted application, aka Android internal bug 30102557 and Qualcomm internal bug CR 789704.
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Analysis
by VulDB Data Team • 09/22/2022
The vulnerability described in CVE-2016-3934 represents a critical buffer overflow condition within the Qualcomm camera driver component of Android operating systems. This flaw exists in the msm_camera_cci_i2c.c file which handles camera sensor communication through the Common Command Interface protocol. The vulnerability specifically manifests when the driver processes variable-length arrays without proper bounds checking, creating a predictable exploitation vector for privilege escalation attacks. The affected devices include Nexus 5, Nexus 5X, Nexus 6, Nexus 6P, and Android One models, all of which were released prior to the security patch date of October 5, 2016, making them susceptible to this widespread vulnerability.
The technical implementation of this vulnerability stems from improper memory management within the camera driver's communication layer. When a malicious application attempts to communicate with the camera hardware through the I2C interface, the driver allocates memory based on user-supplied parameters that define the length of data arrays. This variable-length array allocation pattern creates a classic buffer overflow scenario where attacker-controlled data can overwrite adjacent memory locations. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, occurring in the context of a privileged driver component that operates with elevated system permissions. The flaw allows an unprivileged application to potentially execute arbitrary code with kernel-level privileges, effectively bypassing Android's security model and creating a path for full system compromise.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise and data theft capabilities. An attacker with a crafted application can leverage this vulnerability to gain root access to the device, enabling them to install malicious software, extract sensitive user data, modify system configurations, or establish persistent backdoors. The vulnerability affects devices running Android versions prior to the October 2016 security patch, making millions of devices potentially vulnerable in the wild. The attack vector is particularly concerning because it requires no physical access to the device and can be exploited through standard application installation, making it a prime target for mobile malware distribution. This vulnerability aligns with ATT&CK technique T1068 which describes local privilege escalation and T1543 which covers persistence mechanisms that can be established through kernel-level exploits.
Mitigation strategies for CVE-2016-3934 focus primarily on applying the relevant security patches released by Google and Qualcomm. Device users must ensure their systems are updated to Android security patch level 2016-10-05 or later, which includes the necessary fixes to prevent the variable-length array overflow in the camera driver. Organizations should implement proactive patch management policies to ensure all affected devices receive timely updates. Additionally, security researchers recommend monitoring for any unauthorized applications that might attempt to exploit this vulnerability and implementing application whitelisting policies to prevent installation of untrusted code. The vulnerability highlights the importance of secure coding practices in kernel-level drivers, particularly regarding input validation and memory management. Security professionals should also consider implementing device monitoring solutions that can detect anomalous camera driver behavior that might indicate exploitation attempts, as the vulnerability can be used to establish persistent access to compromised devices.