CVE-2012-3726 in iOS
Summary
by MITRE
Double free vulnerability in ImageIO in Apple iOS before 6 allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted JPEG image.
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Analysis
by VulDB Data Team • 07/22/2018
The CVE-2012-3726 vulnerability represents a critical double free error in Apple iOS ImageIO framework affecting versions prior to iOS 6. This flaw resides in the JPEG image processing component where improper memory management leads to a situation where the same memory block is freed twice during image parsing operations. The vulnerability stems from insufficient input validation and memory deallocation routines within the image decoding pipeline, creating a condition where maliciously crafted JPEG files can trigger unintended memory behavior.
The technical exploitation of this vulnerability occurs when an attacker crafts a specially malformed JPEG image that, when processed by the iOS ImageIO framework, causes the memory allocator to attempt freeing the same memory region twice. This double free condition creates a predictable memory state that can be leveraged by attackers to manipulate heap metadata or overwrite critical data structures. The flaw manifests through the JPEG parser's handling of malformed image headers and compressed data segments, particularly in how it manages memory allocation for image buffers and metadata structures during decompression operations. The vulnerability is classified under CWE-415 as an improper double free condition, which directly enables arbitrary code execution through memory corruption attacks.
When exploited, this vulnerability can result in either remote code execution or denial of service depending on the attacker's objective and the specific memory state at exploitation time. The application crash occurs when the heap corruption leads to invalid memory access patterns, causing the iOS application or system process to terminate unexpectedly. However, under specific conditions, attackers can manipulate the heap layout to achieve code execution by overwriting function pointers or return addresses in memory. The operational impact extends beyond individual application crashes to potentially affect system stability and security boundaries, as the vulnerability exists within a core framework that handles image processing for multiple system components and applications.
The exploitation of this vulnerability requires remote delivery of malicious JPEG content through various attack vectors including email attachments, web content, or file sharing services. The attack surface is extensive given that iOS devices process JPEG images automatically when displaying email attachments, browsing websites, or opening files from various sources. Mitigation strategies include applying the iOS 6.0 update which addresses the memory management issues in the ImageIO framework, implementing strict image validation policies at network boundaries, and deploying application sandboxing measures to limit potential impact. Organizations should also consider network-based intrusion detection systems that can identify and block malicious JPEG content before it reaches end-user devices, as well as implementing mobile device management policies that enforce timely security updates. The vulnerability demonstrates the importance of proper memory management in security-critical components and aligns with ATT&CK technique T1059.007 for execution through image processing frameworks, highlighting the need for comprehensive security testing of input validation and memory handling routines in mobile operating systems.