CVE-2020-0244 in Android
Summary
by MITRE • 12/15/2020
In writeBurstBufferBytes of SPDIFEncoder.cpp, there is a possible out of bounds read due to an incorrect bounds check. This could lead to local information disclosure with no clear exfiltration path, with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-145262423
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Analysis
by VulDB Data Team • 12/18/2020
The vulnerability identified as CVE-2020-0244 resides within the SPDIFEncoder.cpp component of Android's media processing stack, specifically within the writeBurstBufferBytes function. This flaw represents a classic out-of-bounds read condition that occurs when the system performs an incorrect bounds check during audio data processing operations. The vulnerability manifests in Android 11 builds and is tracked under Android ID A-145262423, indicating its classification within Google's internal vulnerability tracking system. The issue stems from insufficient validation of buffer boundaries when handling digital audio data transmission through the SPDIF (Sony/Philips Digital Interface) protocol, which is commonly used for high-quality audio transmission between devices.
The technical implementation of this vulnerability involves a scenario where the writeBurstBufferBytes function fails to properly validate array indices or buffer limits before accessing memory locations. When processing audio data streams, the function calculates buffer positions and attempts to write data to specific memory locations without adequate bounds verification. This incorrect bounds checking allows for potential memory access beyond the allocated buffer boundaries, creating an information disclosure risk. The vulnerability's classification as a local information disclosure means that an attacker must first establish a foothold on the device through other means, as no additional execution privileges are required for exploitation once the condition is triggered. The attack requires user interaction, suggesting that the vulnerability can be triggered through legitimate user activities such as playing specific audio content or connecting to certain audio devices.
From an operational impact perspective, this vulnerability creates a potential information leakage scenario that could expose sensitive data stored in memory regions adjacent to the affected buffer. While the vulnerability does not provide direct execution capabilities, the information disclosure aspect can reveal confidential data such as cryptographic keys, user credentials, or proprietary application data that may be stored in memory. The lack of clear exfiltration path indicates that while data can be read from memory, the attacker cannot directly transmit it to external systems without additional exploitation techniques. This limitation reduces the immediate severity but still represents a significant privacy and security concern, particularly in environments where devices may be compromised through social engineering or other attack vectors. The vulnerability's presence in the SPDIF audio processing pipeline suggests that any device with audio capabilities and SPDIF support could potentially be affected, making it relevant across various Android device types including smartphones, tablets, and wearable devices.
Mitigation strategies for this vulnerability should focus on implementing proper bounds checking mechanisms within the writeBurstBufferBytes function and other similar audio processing functions. System administrators and device manufacturers should prioritize applying the relevant Android security patches that address this specific bounds checking issue. The fix typically involves strengthening the validation logic to ensure that all buffer access operations include proper boundary checks before memory access occurs. Additionally, implementing memory protection mechanisms such as stack canaries, address space layout randomization, and other exploit mitigation techniques can help reduce the potential impact of similar vulnerabilities. Organizations should also consider monitoring for unusual audio processing activities that might indicate exploitation attempts. The vulnerability's alignment with CWE-129 indicates it follows a well-documented pattern of improper input validation leading to memory safety issues, and its potential mapping to ATT&CK technique T1059.007 for process injection or T1005 for data from local system suggests that exploitation might occur through audio processing services that could be leveraged for further system compromise. Regular security audits of audio processing components and implementation of robust input validation practices across all media handling functions can help prevent similar issues from emerging in future software versions.