CVE-2016-3862 in Android
Summary
by MITRE
media/ExifInterface.java 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 2016-09-01 does not properly interact with the use of static variables in libjhead_jni, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted media file, aka internal bug 29270469.
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Analysis
by VulDB Data Team • 09/15/2022
The vulnerability described in CVE-2016-3862 represents a critical memory corruption flaw within the Android media processing framework that affects multiple versions of the operating system. This vulnerability exists in the media/ExifInterface.java component of the mediaserver process, which is responsible for handling image metadata processing in Android devices. The flaw specifically manifests when the mediaserver interacts with static variables within the libjhead_jni library, creating a dangerous condition where remote attackers can manipulate media files to trigger unintended code execution or system instability.
The technical root cause of this vulnerability stems from improper handling of static variables within the native JNI (Java Native Interface) layer that processes Exif metadata. Static variables maintain their state across multiple function calls and object instances, but when improperly managed in multithreaded environments like the mediaserver, they can lead to race conditions and memory corruption scenarios. The libjhead_jni library, which is responsible for JPEG header processing, contains static data structures that are not properly synchronized or reset between different media file processing operations. This creates a situation where maliciously crafted media files can exploit the predictable memory layout and static variable states to overwrite critical memory regions, potentially leading to arbitrary code execution or denial of service conditions.
The operational impact of this vulnerability is severe as it allows remote attackers to execute arbitrary code on affected Android devices simply by enticing users to view or process specially crafted media files. This creates a significant attack surface since media files are commonly shared through various channels including email attachments, messaging applications, social media platforms, and web downloads. The vulnerability affects a broad range of Android versions including 4.x through 6.x, making it particularly dangerous as it could compromise millions of devices across different generations of the Android operating system. The memory corruption can manifest in various ways including heap corruption, stack overflow conditions, or null pointer dereferences that can lead to complete system crashes or unauthorized code execution.
This vulnerability aligns with CWE-676 (Use of Potentially Dangerous Function) and CWE-121 (Stack-based Buffer Overflow) categories, as it involves unsafe memory handling patterns and improper variable management in native code. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 (Command and Scripting Interpreter: JavaScript) and T1203 (Exploitation for Client Execution) as attackers can leverage this flaw to execute malicious code on target devices. The vulnerability also demonstrates characteristics of T1190 (Exploit Public-Facing Application) since it can be triggered through publicly accessible media processing functionality. The lack of proper input validation and memory boundary checking in the Exif metadata parsing process creates an ideal environment for attackers to craft malicious payloads that exploit the static variable interaction patterns within the libjhead_jni library.
Mitigation strategies for this vulnerability require immediate patching of affected Android versions, with system administrators and device manufacturers prioritizing the deployment of security updates that address the static variable handling issues in the media processing components. The recommended approach includes implementing proper synchronization mechanisms for static variables, adding comprehensive input validation for media files, and ensuring proper memory cleanup between processing operations. Additionally, users should avoid opening media files from untrusted sources and organizations should consider implementing network-level filtering to prevent potentially malicious media files from reaching end-user devices. The fix typically involves modifying the ExifInterface.java code to properly manage static variable states and ensuring that the native JNI layer properly resets or isolates static data between different media file processing sessions to prevent cross-contamination of memory states.