CVE-2016-2478 in Android
Summary
by MITRE
mm-video-v4l2/vidc/vdec/src/omx_vdec_msm8974.cpp in mediaserver in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-06-01 mishandles pointers, which allows attackers to gain privileges via a crafted application, as demonstrated by obtaining Signature or SignatureOrSystem access, aka internal bug 27475409.
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Analysis
by VulDB Data Team • 01/18/2019
The vulnerability identified as CVE-2016-2478 resides within the multimedia video decoding component of Android's mediaserver process, specifically in the OMX video decoder implementation for the msm8974 platform. This flaw manifests in the omx_vdec_msm8974.cpp file where improper pointer handling occurs during video decoding operations. The vulnerability affects multiple Android versions including 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before the 2016-06-01 security patch release, representing a critical privilege escalation vector that can be exploited by malicious applications.
The technical exploitation of this vulnerability stems from inadequate pointer validation within the video decoding pipeline where attackers can manipulate memory pointers to gain elevated privileges. When a crafted application attempts to decode malicious video content through the affected OMX decoder, the improper pointer handling allows for memory corruption that can be leveraged to escalate privileges. The vulnerability specifically enables attackers to obtain Signature or SignatureOrSystem level access, which represents a significant escalation from the typical application permissions. This privilege level grants access to system-level functionality including the ability to install applications with system-level privileges and access protected system resources.
From an operational perspective, this vulnerability represents a severe security risk as it allows any installed application to potentially gain system-level control over the device. The exploitation requires only a crafted application that triggers the vulnerable video decoding path, making it particularly dangerous as it can be delivered through standard app distribution channels. The vulnerability's impact extends beyond simple privilege escalation to include potential full device compromise, as the elevated privileges enable access to sensitive system components, user data, and the ability to modify system files. This makes it a prime target for malware authors seeking persistent access to Android devices.
The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic case of improper pointer management that can lead to privilege escalation. According to ATT&CK framework, this vulnerability maps to privilege escalation techniques where adversaries leverage software flaws to gain higher-level system permissions. The attack vector follows the pattern of code execution in a privileged context, where the mediaserver process executes with elevated privileges due to its role in system multimedia services. The mitigation strategy requires immediate patching of affected Android versions, with the security updates addressing the pointer handling issues in the OMX video decoder implementation. Additionally, system administrators should implement application whitelisting policies and monitor for suspicious application behavior that might indicate exploitation attempts, particularly around media processing activities.