CVE-2021-0964 in Android
Summary
by MITRE • 12/15/2021
In C2SoftMP3::process() of C2SoftMp3Dec.cpp, there is a possible out of bounds write due to a heap buffer overflow. This could lead to remote information disclosure with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-10 Android-11 Android-12 Android-9Android ID: A-193363621
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Analysis
by VulDB Data Team • 12/18/2021
This vulnerability exists within the C2SoftMP3::process() function of the C2SoftMp3Dec.cpp file, representing a critical heap buffer overflow flaw that affects multiple Android versions including Android 9, 10, 11, and 12. The vulnerability stems from improper bounds checking during audio decoding operations, specifically when processing MP3 files through the C2SoftMP3 decoder component. The flaw manifests as an out of bounds write condition that can occur when the decoder attempts to write data beyond the allocated heap buffer boundaries. This type of vulnerability falls under CWE-121, heap-based buffer overflow, which is classified as a serious memory safety issue that can lead to arbitrary code execution or information disclosure. The vulnerability is particularly concerning because it enables remote information disclosure without requiring any additional execution privileges beyond normal user interaction, making it accessible to attackers who can simply deliver a malicious MP3 file to trigger the exploit. The Android ID A-193363621 indicates this was tracked by Google's security team as a significant concern requiring immediate attention.
The technical implementation of this vulnerability occurs during the MP3 decoding process where the C2SoftMP3 decoder fails to properly validate input parameters before writing to heap-allocated memory buffers. When processing malformed MP3 files, the decoder's buffer management logic does not adequately check array bounds, allowing an attacker to craft specially designed audio files that cause the decoder to write data beyond the intended buffer limits. This out of bounds write can overwrite adjacent memory locations, potentially corrupting critical data structures or leaking sensitive information from the application's memory space. The vulnerability requires user interaction for exploitation, typically through the delivery of malicious media files via email attachments, messaging applications, or web downloads, making it particularly dangerous in real-world scenarios. The flaw operates at the media framework level within Android's stagefright subsystem, which handles multimedia processing for various applications, thereby amplifying its potential impact across the entire Android ecosystem.
The operational impact of CVE-2021-0964 extends beyond simple information disclosure to potentially enable more severe attacks within the Android security model. While the vulnerability does not require additional execution privileges, the heap buffer overflow can be leveraged to achieve arbitrary code execution in certain scenarios, particularly when combined with other vulnerabilities or when the target system has specific memory layout characteristics. The remote information disclosure aspect means that attackers can potentially extract sensitive data from memory locations, including application credentials, personal information, or cryptographic keys that may be stored in adjacent memory regions. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, as it can serve as a foundation for more sophisticated attacks. The widespread adoption of affected Android versions means that millions of devices could be potentially compromised, with the vulnerability affecting devices across multiple generations of Android releases, making it a high-priority security concern for both device manufacturers and end users.
Mitigation strategies for this vulnerability should focus on immediate patch deployment through official Android security updates, which typically include memory bounds checking improvements and input validation enhancements within the media framework. Device manufacturers should prioritize rolling out security patches to affected Android versions, particularly targeting the C2SoftMP3 decoder component and related media processing libraries. Users should ensure their devices are updated to the latest security patches and avoid downloading media files from untrusted sources. Network administrators should implement content filtering measures to block potentially malicious MP3 files, particularly in enterprise environments where device security is paramount. The vulnerability highlights the importance of robust memory safety practices in media processing components and underscores the need for comprehensive input validation and bounds checking in all heap-based operations. Security monitoring should include detection of unusual media processing behavior and memory access patterns that could indicate exploitation attempts. Organizations should also consider implementing additional security controls such as application sandboxing and memory protection mechanisms to limit the potential impact of similar vulnerabilities in the future.