CVE-2012-3756 in QuickTime
Summary
by MITRE
Buffer overflow in Apple QuickTime before 7.7.3 allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted rnet box in an MP4 movie file.
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Analysis
by VulDB Data Team • 04/19/2021
The vulnerability identified as CVE-2012-3756 represents a critical buffer overflow flaw in Apple QuickTime media player software versions prior to 7.7.3. This vulnerability specifically affects the handling of rnet boxes within MP4 movie files, creating a dangerous condition that can be exploited by remote attackers to gain unauthorized execution privileges or cause system instability. The flaw exists in the parsing logic of QuickTime's multimedia framework when processing malformed rnet box structures, which are part of the MP4 container format used for storing audiovisual content.
The technical implementation of this vulnerability stems from improper bounds checking during the processing of rnet boxes in MP4 files. When QuickTime encounters a crafted rnet box structure, the application fails to validate the size or content of the box before attempting to copy data into fixed-size buffers. This classic buffer overflow condition allows an attacker to overwrite adjacent memory locations with malicious data, potentially leading to arbitrary code execution. The vulnerability operates at the application layer and requires no special privileges to exploit, making it particularly dangerous as it can be triggered through simple media file playback. The flaw maps directly to CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory regions.
The operational impact of CVE-2012-3756 extends beyond simple application crashes to encompass full system compromise potential. Remote attackers can craft malicious MP4 files that, when opened by an affected QuickTime version, will trigger the buffer overflow and potentially execute arbitrary code with the privileges of the user running the application. This creates a significant threat vector for phishing campaigns, malicious file sharing, and targeted attacks against vulnerable systems. The vulnerability affects a wide range of Apple operating systems including macOS versions that ship with QuickTime 7.7.2 or earlier, making it particularly impactful given QuickTime's widespread installation base. The attack surface is further expanded by the fact that MP4 files are commonly shared through email attachments, web downloads, and file sharing platforms.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1203, which covers exploitation of software vulnerabilities for privilege escalation and code execution. The attack chain typically involves delivery of a malicious MP4 file through social engineering or automated download mechanisms, followed by user interaction that triggers the QuickTime parsing routine. Organizations should consider implementing network-based protections such as content filtering and sandboxing solutions to mitigate exposure. The recommended mitigation strategy includes immediate deployment of Apple's security patches updating QuickTime to version 7.7.3 or later, along with network segmentation and user education to prevent accidental execution of untrusted media files. Additionally, system administrators should consider disabling QuickTime plugin support in web browsers and implementing automated patch management processes to ensure timely remediation of similar vulnerabilities.