CVE-2014-7933 in Chrome
Summary
by MITRE
Use-after-free vulnerability in the matroska_read_seek function in libavformat/matroskadec.c in FFmpeg before 2.5.1, as used in Google Chrome before 40.0.2214.91, allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted Matroska file that triggers improper maintenance of tracks data.
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Analysis
by VulDB Data Team • 03/06/2022
The CVE-2014-7933 vulnerability represents a critical use-after-free flaw in the FFmpeg multimedia processing library that affected numerous applications including Google Chrome. This vulnerability specifically resides in the matroska_read_seek function within the libavformat/matroskadec.c file, which handles Matroska container format parsing. The flaw manifests when processing crafted Matroska files that contain malformed track data structures, creating a scenario where memory that has been freed is subsequently accessed, leading to unpredictable behavior. The vulnerability impacts FFmpeg versions prior to 2.5.1 and affected Google Chrome versions before 40.0.2214.91, making it particularly dangerous as it could be exploited through web-based media playback scenarios. The improper maintenance of tracks data during the seek operation creates a condition where freed memory pointers are dereferenced, potentially allowing attackers to execute arbitrary code or cause denial of service conditions.
The technical exploitation of this vulnerability involves crafting a malicious Matroska file that triggers the specific code path within the matroska_read_seek function. When the media player attempts to seek within the file, the function fails to properly manage the lifecycle of track data structures, leading to a use-after-free condition. This type of vulnerability falls under CWE-416, which specifically addresses the use of freed memory, and can be categorized under the broader ATT&CK technique T1203 for legitimate system exploitation. The flaw demonstrates poor memory management practices where allocated memory for track metadata is freed but references to that memory remain in the program's execution path. Attackers can leverage this by creating specially crafted Matroska files that cause the application to free memory structures while maintaining references to them, potentially leading to memory corruption that can be exploited for code execution.
The operational impact of CVE-2014-7933 extends beyond simple denial of service scenarios to potentially enable remote code execution, making it a severe security concern for applications that process multimedia content. When exploited, this vulnerability could allow remote attackers to execute arbitrary code on vulnerable systems, particularly those running affected versions of Chrome or other applications that utilize the vulnerable FFmpeg library. The vulnerability's exploitation requires only a maliciously crafted media file, making it highly accessible to threat actors and potentially affecting a wide range of users. The memory corruption resulting from the use-after-free condition can be leveraged to overwrite critical program data, manipulate execution flow, or cause system instability. The vulnerability's presence in widely-used software like Google Chrome means that successful exploitation could lead to widespread compromise of user systems, particularly in environments where users frequently access untrusted media content through web browsers.
Mitigation strategies for CVE-2014-7933 primarily focus on updating to patched versions of the affected software components. Organizations should immediately upgrade to FFmpeg version 2.5.1 or later, and ensure that Google Chrome is updated to version 40.0.2214.91 or higher to address this vulnerability. Additionally, implementing content filtering and sandboxing measures can provide defense-in-depth protection, particularly in environments where users may encounter untrusted media content. The vulnerability highlights the importance of proper memory management in multimedia processing libraries and demonstrates the need for rigorous code review processes, especially for functions that handle complex data structures and memory allocation patterns. Security professionals should monitor for similar vulnerabilities in multimedia processing libraries and implement automated patch management systems to ensure timely remediation of such critical flaws. The vulnerability also underscores the necessity of employing static and dynamic analysis tools during software development to identify potential memory management issues before they can be exploited in production environments.