CVE-2012-1133 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 write operation and memory corruption) or possibly execute arbitrary code via crafted glyph or bitmap data in a BDF font.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 04/13/2021
The vulnerability identified as CVE-2012-1133 represents a critical heap-based buffer overflow flaw within the FreeType font rendering library that affects numerous applications including Mozilla Firefox Mobile versions prior to 10.0.4. This vulnerability stems from insufficient input validation when processing BDF font files, which are bitmap font formats commonly used in X Window System environments. The flaw exists in the FreeType library version 2.4.8 and earlier, making it a widespread issue across many software products that rely on this font rendering component for proper display functionality.
The technical exploitation of this vulnerability occurs through malformed glyph or bitmap data embedded within BDF font files that are processed by the vulnerable FreeType library. When the library attempts to parse and render these crafted font elements, it fails to properly validate the size parameters and memory allocation requirements, leading to an invalid heap write operation. This memory corruption can manifest in two primary ways: either causing a denial of service through application crashes or potentially enabling remote code execution if the attacker can control the memory layout and overwrite critical program structures. The vulnerability specifically targets the heap memory management functions within the FreeType library's font parsing routines, making it particularly dangerous as it can be triggered through normal font rendering operations.
From an operational perspective, this vulnerability presents significant risks to mobile and desktop applications that utilize FreeType for font rendering, particularly in environments where users may encounter untrusted font content. The impact extends beyond simple browser applications to include any software that integrates FreeType as a font processing component, potentially affecting entire operating system ecosystems that rely on this library for proper display functionality. The vulnerability's remote exploitability means that attackers can trigger the flaw through web content, email attachments, or any mechanism that allows users to process potentially malicious font files without proper user interaction. This makes it particularly dangerous in mobile environments where users may be more susceptible to phishing attacks and where application sandboxing may be less restrictive than desktop systems.
Organizations should prioritize immediate patching of all affected FreeType library versions, specifically upgrading to version 2.4.9 or later where the vulnerability has been addressed through improved input validation and memory allocation checks. System administrators should implement network segmentation and application whitelisting policies to prevent untrusted font content from being processed by vulnerable applications. Additionally, regular security assessments should verify that all applications utilizing FreeType have been updated to secure versions, with particular attention to mobile applications and embedded systems that may not receive automatic updates. The vulnerability aligns with CWE-121, heap-based buffer overflow, and maps to ATT&CK technique T1059.007 for remote code execution through malformed input processing, highlighting the need for comprehensive input validation across all font processing components within affected software ecosystems.