CVE-2019-2158 in Android
Summary
by MITRE
In libxaac, there is a possible out of bounds read due to a missing bounds check. This could lead to information disclosure with no additional execution privileges needed. User interaction is needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-118766492
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Analysis
by VulDB Data Team • 09/11/2020
The vulnerability identified as CVE-2019-2158 affects the libxaac library component within Android systems, specifically Android 10 and related versions. This issue represents a critical out-of-bounds read condition that stems from insufficient input validation and bounds checking mechanisms. The flaw exists within the audio decoding subsystem where the libxaac library processes audio data, creating a potential security risk that could expose sensitive information to unauthorized parties.
The technical implementation of this vulnerability manifests when the libxaac library fails to properly validate the size and boundaries of audio data structures during processing. This missing bounds check allows an attacker to craft specially malformed audio files that, when processed by the vulnerable library, can cause the application to read memory locations beyond the intended buffer boundaries. The absence of proper validation means that the library does not verify that audio data parameters fall within acceptable ranges before attempting to access memory regions. This condition typically occurs during the parsing of Advanced Audio Coding (AAC) audio files where the library expects specific data structures but receives corrupted or maliciously crafted input.
The operational impact of this vulnerability extends beyond simple information disclosure, as it represents a fundamental weakness in Android's audio processing pipeline that could potentially be exploited to gain insights into system memory layout or extract confidential data. While the vulnerability requires user interaction for exploitation, meaning a malicious audio file must be intentionally played or processed by the target system, the lack of additional execution privileges needed makes it particularly concerning. The attack vector typically involves social engineering or phishing campaigns where users are诱导 to play malicious audio content, which then triggers the out-of-bounds read condition. This vulnerability aligns with CWE-129, which specifically addresses improper validation of array indices, and represents a classic example of how insufficient bounds checking can lead to memory corruption issues.
The exploitation of this vulnerability demonstrates a sophisticated understanding of Android's multimedia processing architecture and the specific implementation details of the libxaac library. Attackers can leverage this weakness by creating audio files that contain malformed data structures designed to trigger the missing bounds check, causing the system to read beyond allocated memory regions. The information disclosure aspect of this vulnerability could potentially reveal sensitive system information such as memory addresses, cryptographic keys, or other confidential data that resides in adjacent memory locations. Security researchers have noted that this type of vulnerability often serves as a stepping stone for more complex attacks, as the extracted information can be used to bypass security mitigations or aid in developing more sophisticated exploitation techniques. The ATT&CK framework categorizes this vulnerability under the information disclosure tactic, where adversaries attempt to access or extract sensitive data from target systems through software weaknesses.
Mitigation strategies for CVE-2019-2158 primarily focus on updating the affected Android system to versions that include patches addressing the bounds checking deficiency in libxaac. Android security updates typically include comprehensive fixes for such vulnerabilities, often involving code modifications that implement proper input validation and bounds checking mechanisms. Organizations should prioritize immediate deployment of security patches to ensure that all affected devices are protected against potential exploitation attempts. Additionally, network administrators should consider implementing additional security controls such as audio file filtering or sandboxing mechanisms to prevent the processing of untrusted audio content. The fix typically involves adding proper validation checks before any memory access operations, ensuring that all array indices and data structure parameters are verified against expected ranges. System administrators should also monitor for any unusual audio processing activities or memory access patterns that might indicate exploitation attempts. The vulnerability highlights the importance of robust input validation in multimedia processing libraries and underscores the need for comprehensive security testing of system components that handle user-provided data.