CVE-2014-9777 in Android
Summary
by MITRE
The vid_dec_set_meta_buffers function in drivers/video/msm/vidc/common/dec/vdec.c in the Qualcomm components in Android before 2016-07-05 on Nexus 5 and 7 (2013) devices does not validate the number of buffers, which allows attackers to gain privileges via a crafted application, aka Android internal bug 28598501 and Qualcomm internal bug CR563654.
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Analysis
by VulDB Data Team • 09/01/2022
The vulnerability described in CVE-2014-9777 represents a critical privilege escalation flaw within the Android operating system's video decoding component. This issue affects Qualcomm-based Android devices, specifically the Nexus 5 and Nexus 7 (2013) models, and was present in Android versions prior to the 2016-07-05 security update. The vulnerability stems from insufficient input validation within the video decoder's metadata buffer management function, creating a pathway for malicious applications to execute arbitrary code with elevated privileges. The flaw is particularly concerning as it allows attackers to exploit a legitimate system component to gain unauthorized access to system resources, potentially compromising the entire device.
The technical root cause of this vulnerability lies in the vid_dec_set_meta_buffers function located in the drivers/video/msm/vidc/common/dec/vdec.c file within the Qualcomm multimedia subsystem. This function fails to properly validate the number of buffers specified by incoming requests, creating a buffer over-read or buffer under-read condition that can be exploited to manipulate memory structures. The lack of proper bounds checking means that an attacker can supply an excessive number of buffer requests that exceed the allocated memory space, potentially leading to memory corruption that can be leveraged for privilege escalation. This type of vulnerability falls under the CWE-129 category of "Improper Validation of Array Index" and represents a classic example of how insufficient input validation can lead to critical security weaknesses.
The operational impact of CVE-2014-9777 extends beyond simple privilege escalation, as it provides attackers with a persistent foothold on affected devices. Once exploited, this vulnerability allows malicious applications to execute code with kernel-level privileges, potentially enabling complete device compromise. Attackers could leverage this weakness to install malicious applications, access sensitive user data, modify system files, or establish persistent backdoors. The vulnerability's presence in the video decoding subsystem means that even routine media playback activities could serve as attack vectors, making it particularly dangerous as it operates within a component that is frequently accessed by legitimate applications. This aligns with ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation" and demonstrates how system-level vulnerabilities can be exploited to gain elevated access.
The exploitation of this vulnerability requires a crafted application that can manipulate the video decoding subsystem to trigger the buffer validation failure. Attackers typically need to construct malicious media files or application payloads that cause the video decoder to process an excessive number of buffers, leading to memory corruption. The vulnerability affects devices running Android versions prior to July 2016, making it particularly relevant for users who have not updated their systems. Organizations and individuals should prioritize immediate patching of affected devices and consider implementing additional security controls such as application whitelisting, monitoring for suspicious buffer operations, and regular security assessments of mobile device environments. The vulnerability highlights the importance of comprehensive input validation in system-level components and demonstrates how seemingly benign functionality can become a critical security risk when proper validation mechanisms are absent.