CVE-2017-12839 in mpg123
Summary
by MITRE
A heap-based buffer over-read in the getbits function in src/libmpg123/getbits.h in mpg123 through 1.25.5 allows remote attackers to cause a possible denial-of-service (out-of-bounds read) or possibly have unspecified other impact via a crafted mp3 file.
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Analysis
by VulDB Data Team • 09/15/2023
The vulnerability identified as CVE-2017-12839 represents a critical heap-based buffer over-read condition affecting the mpg123 media player library version 1.25.5 and earlier. This flaw exists within the getbits function located in the src/libmpg123/getbits.h source file, which is responsible for extracting bits from the bitstream during mp3 file decoding operations. The vulnerability manifests when processing specially crafted mp3 files that contain malformed bitstream data, potentially leading to unauthorized memory access patterns that exceed the bounds of allocated heap memory regions.
The technical implementation of this vulnerability stems from insufficient input validation and boundary checking within the bit extraction logic. When mpg123 attempts to read bits from a malformed mp3 file, the getbits function fails to properly validate the expected bitstream structure, allowing an attacker to manipulate the decoding process through carefully constructed file contents. This over-read condition occurs because the function does not adequately verify that bit positions and data lengths remain within acceptable memory boundaries, potentially causing the application to access memory locations that have not been allocated for the current operation. The flaw falls under the CWE-125 vulnerability category, which specifically addresses out-of-bounds read conditions in memory management operations.
The operational impact of CVE-2017-12839 extends beyond simple denial-of-service scenarios to potentially enable more sophisticated attacks depending on the execution environment. Remote attackers can leverage this vulnerability to trigger out-of-bounds memory reads that may result in application crashes, leading to denial-of-service conditions for legitimate users. In certain configurations, particularly when mpg123 is used in server applications or integrated into larger software ecosystems, this vulnerability could potentially be exploited to gather sensitive memory information or even facilitate further exploitation attempts. The ATT&CK framework categorizes this as a memory corruption technique, specifically under the T1068 privilege escalation tactic, where initial access through malformed media files could lead to broader system compromise.
Mitigation strategies for CVE-2017-12839 should prioritize immediate patching of affected mpg123 installations to version 1.25.6 or later, which contains the necessary fixes for the buffer over-read condition. System administrators should implement strict input validation for all mp3 files processed by applications using mpg123, including file format verification and content scanning before decoding operations. Additionally, deployment of intrusion detection systems capable of identifying malformed mp3 file patterns and network-based filtering rules can help prevent exploitation attempts. Organizations should also consider implementing application sandboxing techniques and memory protection mechanisms such as stack canaries and address space layout randomization to reduce the potential impact of any successful exploitation attempts. The vulnerability demonstrates the critical importance of robust input validation in multimedia processing libraries and highlights the need for comprehensive security testing of media decoding components against adversarial input patterns.