CVE-2019-9335 in Android
Summary
by MITRE
In libavc there is a possible information disclosure due to uninitialized data. This could lead to remote information disclosure with no additional execution privileges needed. User interaction is needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-112328051
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Analysis
by VulDB Data Team • 09/12/2020
The vulnerability identified as CVE-2019-9335 resides within the libavc component of Android systems, specifically affecting Android 10 releases. This issue represents a critical information disclosure flaw that stems from the improper handling of uninitialized data structures during video processing operations. The vulnerability manifests when the system processes certain video streams without properly initializing memory regions, potentially exposing sensitive information to unauthorized parties. The flaw is particularly concerning because it can be exploited remotely without requiring any special privileges or elevated execution rights, making it accessible to attackers with minimal access requirements.
The technical root cause of this vulnerability aligns with CWE-457, which addresses the use of uninitialized variables in software systems. When libavc processes video content, it fails to properly initialize certain memory buffers or data structures before utilizing them in processing operations. This uninitialized data may contain remnants from previous operations or system memory contents, creating potential information leakage pathways. The vulnerability specifically impacts the video decoding and processing pipeline where the system encounters malformed or unexpected video data streams. The uninitialized memory regions can inadvertently reveal information such as stack contents, previous data values, or system memory layouts that could aid attackers in further exploitation attempts.
The operational impact of CVE-2019-9335 extends beyond simple information disclosure, as it creates potential pathways for more sophisticated attacks within the Android security model. Remote exploitation of this vulnerability requires user interaction, typically through the delivery of malicious video content via email attachments, messaging applications, or web-based media streams. Attackers can craft specially formatted video files that trigger the uninitialized data exposure when processed by the vulnerable libavc component. The attack vector operates through the Android media processing framework, where the system's video decoding capabilities are leveraged to execute the information disclosure payload. This vulnerability effectively undermines the principle of least privilege by allowing unauthorized information exposure through normal media processing operations.
The exploitation of this vulnerability follows patterns consistent with the attack technique described in the MITRE ATT&CK framework under the information disclosure category. The attack chain typically begins with the delivery of malicious media content, followed by user interaction to open or process the content, which then triggers the uninitialized data exposure within the libavc component. Security researchers have noted that this vulnerability can potentially expose sensitive data that might include cryptographic keys, system memory contents, or other confidential information that could be leveraged for additional attacks. The remote nature of the exploit means that attackers can operate without physical access to the target device, making it particularly dangerous in mobile environments where users frequently interact with untrusted content.
Mitigation strategies for CVE-2019-9335 focus on both immediate patching and operational security measures. Android users should immediately install the relevant security updates provided by Google, which include fixes for the libavc component and associated media processing libraries. Organizations should implement network-based filtering to block suspicious video content and consider deploying mobile device management solutions that can enforce security policies and prevent the installation of untrusted applications. Additionally, users should exercise caution when opening media files from unknown sources and should keep their devices updated with the latest security patches. The vulnerability highlights the importance of proper memory initialization practices in security-critical components and serves as a reminder of the potential risks associated with uninitialized data handling in mobile operating systems. Security teams should monitor for indicators of compromise related to this vulnerability and consider implementing additional logging and monitoring around media processing activities to detect potential exploitation attempts.