CVE-2011-3221 in Mac OS X
Summary
by MITRE
QuickTime in Apple Mac OS X before 10.7.2 does not properly handle the atom hierarchy in movie files, which allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted file.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 01/19/2025
The vulnerability identified as CVE-2011-3221 represents a critical buffer overflow condition within Apple's QuickTime multimedia framework affecting Mac OS X versions prior to 10.7.2. This flaw resides in the improper handling of atom hierarchy structures within movie files, specifically in how the QuickTime player processes the hierarchical organization of data atoms that define multimedia content. The atom structure serves as the fundamental building block for QuickTime movie files, where each atom contains metadata and data elements that describe various aspects of the multimedia content including audio, video, and timing information.
The technical implementation of this vulnerability stems from insufficient validation of atom boundaries and hierarchical relationships during file parsing operations. When a maliciously crafted QuickTime movie file is processed, the QuickTime player fails to properly validate the structure of nested atoms, leading to memory corruption when attempting to read beyond allocated buffer boundaries. This memory corruption occurs because the parser does not adequately verify the integrity of atom headers, particularly the size fields that define the boundaries of each atom within the file hierarchy. The flaw allows attackers to construct atom structures that cause the parser to allocate insufficient memory for processing, subsequently leading to buffer overflows when the parser attempts to read beyond these boundaries.
The operational impact of this vulnerability extends beyond simple denial of service to encompass full remote code execution capabilities. Attackers can leverage this vulnerability by crafting malicious movie files that, when opened by an affected QuickTime player, trigger the buffer overflow condition. The resulting memory corruption can be exploited to overwrite critical memory locations including return addresses and function pointers, enabling arbitrary code execution within the context of the QuickTime process. This represents a significant escalation from simple application crashes to complete system compromise, as the QuickTime player typically runs with elevated privileges when processing multimedia content. The vulnerability affects both local and remote attack scenarios since QuickTime can be triggered through various means including email attachments, web downloads, or network file transfers.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation in multimedia processing frameworks. The attack vector maps to the ATT&CK technique T1059.007 for execution through multimedia files, and T1203 for exploitation of software vulnerabilities. Organizations running affected versions of Mac OS X face substantial risk as this vulnerability can be exploited through multiple attack surfaces including web browsers that embed QuickTime plugins, email clients that automatically play multimedia attachments, and file sharing applications that process QuickTime content. The vulnerability demonstrates the critical importance of proper memory management and input validation in multimedia frameworks, as these components often handle untrusted data from external sources.
Mitigation strategies for CVE-2011-3221 require immediate system updates to Mac OS X 10.7.2 or later versions where Apple has implemented proper atom validation and boundary checking mechanisms. System administrators should disable QuickTime plugin support in web browsers and implement strict file type filtering for multimedia content. Additionally, network-based mitigations can include content filtering solutions that block suspicious QuickTime movie files and network segmentation to limit exposure. The vulnerability highlights the importance of regular patch management and the need for organizations to maintain current security patches across all multimedia processing components. Security monitoring should include detection of QuickTime-related memory access patterns and unusual file processing activities that may indicate exploitation attempts.