CVE-2021-32277 in FAAD2
Summary
by MITRE • 09/20/2021
An issue was discovered in faad2 through 2.10.0. A heap-buffer-overflow exists in the function sbr_qmf_analysis_32 located in sbr_qmf.c. It allows an attacker to cause code Execution.
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Analysis
by VulDB Data Team • 09/29/2021
The vulnerability identified as CVE-2021-32277 represents a critical heap buffer overflow condition within the faad2 audio decoding library version 2.10.0 and earlier. This issue specifically manifests in the sbr_qmf_analysis_32 function located within the sbr_qmf.c source file, where improper bounds checking allows attackers to manipulate memory allocation patterns. The flaw arises from insufficient validation of input data during the processing of Advanced Audio Coding files, particularly when handling specific bitstream configurations that trigger the vulnerable code path. The heap buffer overflow occurs when the decoder attempts to write data beyond the allocated memory boundaries, potentially leading to arbitrary code execution.
This vulnerability falls under the CWE-121 heap-based buffer overflow category and represents a serious security risk within multimedia processing applications. The attack vector involves crafting malicious audio files that, when processed by software utilizing faad2 as a decoder, trigger the buffer overflow condition. The operational impact extends beyond simple denial of service, as successful exploitation can enable remote code execution on systems running vulnerable applications. This makes the vulnerability particularly dangerous in environments where users might encounter untrusted audio content, such as web browsers, media players, or content management systems that process user-uploaded audio files. The vulnerability affects any software implementation that relies on faad2 for audio decoding, including but not limited to media players, streaming services, and multimedia frameworks.
The exploitation of this vulnerability requires an attacker to prepare specially crafted audio files that contain malformed data structures triggering the specific code path in sbr_qmf_analysis_32. The ATT&CK framework categorizes this as a code injection technique under the T1059.007 sub-technique, specifically targeting memory corruption vulnerabilities. When successfully exploited, the heap buffer overflow can be leveraged to overwrite critical memory locations, potentially allowing an attacker to execute arbitrary code with the privileges of the affected application. This risk is compounded by the widespread adoption of faad2 in various media processing applications, making the attack surface extensive across multiple software ecosystems. The vulnerability demonstrates how seemingly benign multimedia processing functions can become attack vectors when proper input validation and memory management practices are not implemented.
Mitigation strategies should focus on immediate patching of affected systems and implementations to upgrade to faad2 version 2.10.1 or later, which contains the necessary fixes for this heap buffer overflow. Organizations should implement input validation measures and sandboxing techniques when processing untrusted audio content, particularly in web-based environments where users might upload audio files. Additionally, security monitoring should be enhanced to detect unusual memory allocation patterns or potential exploitation attempts. The implementation of address space layout randomization, stack canaries, and other exploit mitigation techniques can provide additional defense-in-depth measures. Regular security assessments and vulnerability scanning should be conducted to identify other potential instances of similar memory corruption issues within multimedia processing pipelines, as this vulnerability highlights the importance of rigorous input validation and memory management practices in audio decoding libraries.