CVE-2015-3689 in Mac OS X
Summary
by MITRE
CoreText in Apple iOS before 8.4 and OS X before 10.10.4 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted text file, a different vulnerability than CVE-2015-3685, CVE-2015-3686, CVE-2015-3687, and CVE-2015-3688.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability identified as CVE-2015-3689 represents a critical memory corruption flaw within Apple's CoreText framework affecting iOS versions prior to 8.4 and OS X versions prior to 10.10.4. This vulnerability resides in the text processing subsystem that handles rich text rendering and font management across Apple's operating systems. The CoreText framework serves as a fundamental component for text display and typography management, making it a prime target for attackers seeking to exploit text parsing functionalities. The flaw specifically manifests when processing crafted text files that contain malformed or maliciously constructed data structures, leading to unpredictable memory behavior and potential system compromise.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within CoreText's text parsing routines. When the framework encounters specially crafted text files containing malformed Unicode sequences, improper font data, or corrupted text encoding structures, it fails to properly validate the input before attempting to process and render the content. This deficiency creates opportunities for attackers to manipulate memory layout through buffer overflows, use-after-free conditions, or other memory corruption patterns. The vulnerability operates at the kernel level text processing functions, where the framework attempts to allocate memory for text rendering operations without sufficient bounds checking or sanitization of user-provided data. According to CWE classification, this vulnerability aligns with CWE-121, heap-based buffer overflow, and CWE-787, out-of-bounds write, as the flaw enables attackers to write data beyond allocated memory boundaries.
The operational impact of CVE-2015-3689 extends beyond simple denial of service scenarios to encompass full remote code execution capabilities. Attackers can leverage this vulnerability through various attack vectors including email attachments, web content, or malicious documents that contain crafted text elements. When a user opens such malicious content, the CoreText framework processes the text file and triggers the memory corruption, potentially allowing remote attackers to execute arbitrary code with the privileges of the affected application. The severity classification places this vulnerability in the high-risk category as it can be exploited without user interaction in certain scenarios, particularly when the malicious content is automatically rendered by applications that utilize CoreText for text display. This vulnerability affects the entire Apple ecosystem and can be exploited across multiple application contexts where text rendering occurs, including email clients, web browsers, and document viewers, making it particularly dangerous for enterprise environments.
Mitigation strategies for CVE-2015-3689 focus primarily on immediate system updates and patch management. Apple released security updates for iOS 8.4 and OS X 10.10.4 that address the memory corruption issues within CoreText by implementing proper input validation, bounds checking, and memory allocation safeguards. Organizations should prioritize immediate deployment of these security patches across all affected systems to eliminate the exploitation risk. Additionally, network administrators can implement content filtering measures to block suspicious text files and limit exposure to potentially malicious content through email gateways and web proxies. The vulnerability's characteristics align with ATT&CK technique T1059.007, which involves the use of scripting languages for execution, as attackers may craft text-based payloads that exploit the CoreText processing pipeline. System monitoring should include detection of unusual memory allocation patterns and potential buffer overflow indicators, while security teams should implement proactive threat hunting to identify any attempted exploitation attempts targeting this specific vulnerability within their network environments.