CVE-2019-2147 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-116474108
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Analysis
by VulDB Data Team • 09/11/2020
The vulnerability identified as CVE-2019-2147 resides within the libxaac library component of Android systems, specifically affecting Android 10 installations. This issue represents a classic out-of-bounds read condition that stems from insufficient input validation mechanisms within the audio decoding framework. The flaw manifests when processing malformed audio data, particularly within Advanced Audio Coding (AAC) streams that the system attempts to decode. The vulnerability is categorized under CWE-125 as an out-of-bounds read, which occurs when the system reads memory locations beyond the allocated buffer boundaries. This particular vulnerability requires user interaction for exploitation, meaning that an attacker must convince a victim to process or play a specially crafted audio file for the exploit to be successful. The absence of additional execution privileges required for exploitation makes this vulnerability particularly concerning as it can be leveraged through passive means such as malicious email attachments or compromised websites.
The technical implementation of this vulnerability occurs within the libxaac library's audio decoding routines where the system fails to validate the size or boundaries of incoming audio data before attempting to read from memory locations. When processing audio frames, the library does not properly verify that the data structure parameters align with the allocated memory space, allowing an attacker to craft malicious audio files that cause the decoder to access memory beyond its intended boundaries. This memory access violation can result in information disclosure, where the system inadvertently reveals sensitive data from adjacent memory locations that may contain other applications' data, system credentials, or cryptographic keys. The vulnerability operates at the application layer within the Android multimedia framework, specifically affecting the audio processing pipeline that handles AAC format decoding. The Android ID A-116474108 indicates this was tracked within Google's internal vulnerability management system, demonstrating the recognition of this issue within the Android security ecosystem.
The operational impact of CVE-2019-2147 extends beyond simple information disclosure, as it represents a potential vector for more sophisticated attacks within the Android security model. While no execution privileges are required for initial exploitation, the information disclosure aspect can provide attackers with valuable insights into system memory layout, application state, or other sensitive data that could be leveraged in subsequent attacks. The vulnerability's requirement for user interaction creates a specific attack surface that aligns with social engineering tactics, making it particularly dangerous in environments where users may be induced to open malicious content. The fact that this affects the libxaac library means that any application or service that processes audio content could potentially be exploited, including web browsers, media players, and messaging applications. From an ATT&CK framework perspective, this vulnerability could be categorized under T1059 for execution through legitimate system utilities and T1068 for privilege escalation if the information disclosed can be used to exploit other system components. The vulnerability also demonstrates the importance of proper bounds checking in multimedia processing libraries, as these components often handle untrusted input from network sources.
Mitigation strategies for CVE-2019-2147 primarily involve updating to patched versions of Android 10 where the vulnerability has been addressed through proper bounds checking mechanisms. System administrators should ensure that all Android devices within their environment are updated to the latest security patches provided by Google, particularly those addressing the libxaac library modifications. The fix typically involves implementing additional input validation checks that verify the size and structure of audio data before processing, preventing the out-of-bounds memory access. Organizations should also implement network-based filtering to block suspicious audio content, particularly when users may be downloading or streaming media from untrusted sources. Security monitoring should include detection of unusual audio processing activities that might indicate exploitation attempts, and application whitelisting can help prevent execution of malicious audio files. The vulnerability serves as a reminder of the critical importance of input validation in multimedia libraries, as these components often process data from untrusted sources and require robust security measures to prevent information disclosure attacks. Regular security assessments of multimedia processing components should be conducted to identify similar bounds checking vulnerabilities that could provide attackers with similar information disclosure capabilities.