CVE-2020-0451 in Android
Summary
by MITRE • 11/10/2020
In sbrDecoder_AssignQmfChannels2SbrChannels of sbrdecoder.cpp, there is a possible out of bounds write due to a heap buffer overflow. This could lead to remote code execution with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-10 Android-11 Android-9 Android-8.0 Android-8.1Android ID: A-158762825
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Analysis
by VulDB Data Team • 12/04/2020
The vulnerability identified as CVE-2020-0451 represents a critical heap buffer overflow in the SBR (Spectral Band Replication) decoder component of Android's media processing stack. This flaw exists within the sbrDecoder_AssignQmfChannels2SbrChannels function located in the sbrdecoder.cpp source file, where improper bounds checking allows malicious data to overwrite adjacent memory regions. The vulnerability specifically affects Android versions 8.0, 8.1, 9, 10, and 11, making it a widespread concern across multiple Android release lines. The flaw stems from insufficient validation of input parameters during the spectral band replication decoding process, which is commonly used in audio compression standards such as AAC (Advanced Audio Coding). This particular implementation does not properly verify array indices or buffer boundaries when mapping QMF (Quadrature Mirror Filter) channels to SBR channels, creating an exploitable condition that can be triggered through malformed audio data.
The operational impact of this vulnerability extends beyond simple memory corruption, as it enables remote code execution without requiring any additional privileges or user interaction beyond the initial exploitation trigger. This characteristic places the vulnerability in the category of critical security flaws that can be exploited over network channels or through malicious media files. Attackers can leverage this buffer overflow to overwrite critical memory locations including function pointers, return addresses, or other control structures within the decoder process, potentially leading to arbitrary code execution. The vulnerability's classification as a heap buffer overflow aligns with CWE-121, which specifically addresses heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory boundaries. The Android ID A-158762825 indicates this was tracked as a significant security concern within Google's internal vulnerability tracking system, reflecting the severity and widespread impact potential.
The exploitation of CVE-2020-0451 requires minimal user interaction, typically through the delivery of malicious audio content that triggers the vulnerable SBR decoder function when processed by the Android media framework. This makes the vulnerability particularly dangerous in environments where users may encounter untrusted audio files through various channels including email attachments, web downloads, or multimedia applications. The vulnerability's presence in the core media decoding libraries means that any application utilizing Android's standard audio processing capabilities could be affected, including the system's built-in media player, web browsers, and third-party applications that rely on Android's media framework. From an ATT&CK perspective, this vulnerability maps to techniques involving code injection and privilege escalation through memory corruption, specifically targeting the execution of malicious code within the context of the media processing service. The lack of additional execution privileges required for exploitation places this vulnerability in a particularly dangerous category, as it eliminates the need for complex privilege escalation techniques and can be exploited directly through standard media processing workflows. Mitigation strategies should focus on immediate patch deployment, input validation improvements, and runtime protections such as address space layout randomization and stack canaries to prevent successful exploitation attempts.