CVE-2019-9391 in Android
Summary
by MITRE
In libxaac, there is a possible out of bounds read due to uninitialized data. This could lead to information disclosure with no additional execution privileges needed. User interaction is needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-111050781
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Analysis
by VulDB Data Team • 09/13/2020
The vulnerability CVE-2019-9391 affects the libxaac library component within Android systems, specifically present in Android 10. This issue represents a critical out-of-bounds read condition that stems from uninitialized data handling within the audio decoding process. The flaw exists in the Advanced Audio Coding (AAC) decoding functionality where the system fails to properly initialize memory variables before use, creating a potential pathway for information disclosure attacks. The vulnerability requires user interaction to be exploited, meaning an attacker must convince a victim to perform a specific action such as opening a malicious file or engaging with crafted media content. This characteristic places the vulnerability in the category of user-mediated attacks that leverage social engineering or phishing techniques to achieve exploitation. The out-of-bounds read condition occurs during audio processing when the system attempts to access memory locations beyond the intended buffer boundaries, potentially exposing sensitive data from adjacent memory regions. This type of vulnerability falls under CWE-457: Use of Uninitialized Variable, which is classified as a fundamental programming error that can lead to unpredictable behavior and information leakage. The security implications extend beyond simple data exposure as the leaked information could potentially include cryptographic keys, system memory contents, or other sensitive operational data that might aid in further exploitation attempts.
The operational impact of this vulnerability within the Android ecosystem is significant as it affects the core audio processing capabilities of the platform. When a user interacts with maliciously crafted audio content, the uninitialized data condition triggers an out-of-bounds memory read that can expose information stored in adjacent memory locations. This information disclosure could potentially reveal system internals, user data, or application memory contents that should remain protected. The vulnerability's requirement for user interaction makes it less likely to be exploited at scale compared to fully automated attacks, but it still represents a serious security concern for Android devices. Attackers could leverage this weakness to gather intelligence about device configurations, application states, or even extract sensitive information that could be used for more sophisticated attacks. The exploitation process typically involves creating specially crafted audio files that trigger the uninitialized variable condition when processed by the libxaac library, making this vulnerability particularly dangerous in environments where users frequently encounter multimedia content from untrusted sources.
Mitigation strategies for CVE-2019-9391 should focus on both immediate patching and operational security measures to protect against exploitation. Android security updates addressing this vulnerability should be applied immediately to all affected devices, as the patch typically involves proper initialization of variables within the audio decoding process. Organizations and individuals should implement robust application whitelisting and media file validation procedures to prevent execution of potentially malicious audio content. Network-level controls such as content filtering and sandboxing mechanisms can provide additional protection by restricting access to untrusted audio files and monitoring for suspicious media processing activities. Security monitoring should include detection of unusual audio processing patterns that might indicate exploitation attempts, particularly focusing on memory access violations or information disclosure events. The vulnerability also highlights the importance of proper code review processes and static analysis tools that can identify uninitialized variable conditions before they reach production environments. Implementing memory safety controls and using modern programming practices that prevent uninitialized data usage can significantly reduce the risk of similar vulnerabilities in audio processing components. Organizations should also consider implementing security training for users to recognize potentially malicious media content and avoid interaction with untrusted sources, as the user interaction requirement makes social engineering attacks particularly effective against this type of vulnerability.