CVE-2012-3716 in Mac OS X
Summary
by MITRE
CoreText in Apple Mac OS X 10.7.x before 10.7.5 allows remote attackers to execute arbitrary code or cause a denial of service (out-of-bounds write or read) via a crafted text glyph.
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Analysis
by VulDB Data Team • 12/14/2021
CVE-2012-3716 represents a critical vulnerability in Apple Mac OS X 10.7.x systems prior to version 10.7.5, specifically within the CoreText framework that handles text rendering and typography processing. This vulnerability stems from improper bounds checking in the text glyph processing routines, creating a condition where maliciously crafted text content can trigger memory corruption errors. The flaw manifests as either out-of-bounds write or read operations when CoreText attempts to process specially constructed glyph data, potentially allowing remote attackers to execute arbitrary code or cause system crashes.
The technical implementation of this vulnerability involves the manipulation of text rendering parameters that CoreText uses to display complex typography and international characters. When the framework encounters malformed glyph data, it fails to validate the boundaries of memory allocations, leading to buffer overflow conditions that can be exploited to overwrite critical memory regions or read unauthorized data segments. This type of vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-787, which covers out-of-bounds write vulnerabilities. The attack vector is particularly concerning as it can be triggered remotely through various text-based inputs including emails, web pages, or document files that contain crafted glyph sequences.
The operational impact of CVE-2012-3716 extends beyond simple denial of service scenarios, as successful exploitation could provide attackers with complete system compromise capabilities. Attackers could leverage this vulnerability to execute malicious code with the privileges of the affected application, potentially leading to unauthorized access, data exfiltration, or persistent system control. The vulnerability affects a wide range of applications that utilize CoreText for text rendering, including web browsers, email clients, and document processors, making it a significant threat to macOS users. This issue also maps to ATT&CK technique T1059.007, which covers command and scripting interpreter usage, as exploitation could enable attackers to establish command execution capabilities within the target environment.
Mitigation strategies for this vulnerability primarily focus on immediate system updates and patches provided by Apple, specifically upgrading to Mac OS X 10.7.5 or later versions where the CoreText bounds checking has been properly implemented. Organizations should also implement network-level filtering to restrict access to potentially malicious text content and consider sandboxing applications that process untrusted text data. Security monitoring should include detection of unusual memory access patterns and potential buffer overflow indicators in system logs. Additionally, users should exercise caution when opening documents or viewing web content from untrusted sources, as these represent common attack vectors for exploiting such text rendering vulnerabilities. The vulnerability demonstrates the critical importance of proper input validation and bounds checking in system libraries that handle user-supplied data, particularly in frameworks that process complex data structures like typography and text rendering.