CVE-2012-1141 in iOS
Summary
by MITRE
FreeType before 2.4.9, as used in Mozilla Firefox Mobile before 10.0.4 and other products, allows remote attackers to cause a denial of service (invalid heap read operation and memory corruption) or possibly execute arbitrary code via a crafted ASCII string in a BDF font.
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Analysis
by VulDB Data Team • 04/13/2021
The vulnerability identified as CVE-2012-1141 represents a critical heap-based buffer overflow condition within the FreeType font rendering library that affects numerous applications including Mozilla Firefox Mobile versions prior to 10.0.4. This flaw resides in the BDF (Bitmap Distribution Format) font parsing component of FreeType, specifically when processing malformed ASCII strings within BDF font files. The vulnerability stems from inadequate input validation and memory management practices during font parsing operations, creating opportunities for remote attackers to manipulate heap memory through specially crafted font content.
The technical exploitation of this vulnerability occurs when a malicious BDF font file contains an ASCII string that exceeds the allocated buffer boundaries during parsing operations. This condition leads to invalid heap read operations and subsequent memory corruption that can result in application crashes or potentially arbitrary code execution. The flaw manifests as a classic buffer overflow scenario where the FreeType library fails to properly bounds-check string data within BDF font structures, allowing attackers to overwrite adjacent memory locations. This type of vulnerability maps directly to CWE-121, which describes heap-based buffer overflow conditions, and represents a significant concern for applications that process untrusted font data.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution in affected systems. When exploited, the vulnerability can cause applications using FreeType to crash unpredictably or behave erratically, leading to service disruption. More critically, successful exploitation can allow attackers to execute arbitrary code with the privileges of the affected application, potentially enabling full system compromise. This risk is particularly elevated in mobile environments where Firefox Mobile was vulnerable, as these platforms often have limited security mitigations compared to desktop systems. The vulnerability's impact aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1499.004 for Endpoint Denial of Service, as it enables both service disruption and potential code execution.
Mitigation strategies for CVE-2012-1141 primarily involve updating to FreeType version 2.4.9 or later, which contains the necessary patches to address the buffer overflow conditions in BDF font parsing. Organizations should also implement comprehensive font validation procedures, including sandboxing font processing operations and restricting the types of font files that can be processed by applications. Network-level protections such as content filtering and application whitelisting can provide additional defense in depth. Security teams should monitor for exploitation attempts through network traffic analysis and application logs, particularly looking for unusual font processing activities. The vulnerability demonstrates the importance of proper input validation and memory management in font rendering libraries, as highlighted by industry best practices in secure coding standards that emphasize bounds checking and defensive programming techniques to prevent similar heap-based vulnerabilities from occurring in future implementations.