CVE-2012-1142 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-outline data in a font.
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Analysis
by VulDB Data Team • 05/01/2018
The vulnerability identified as CVE-2012-1142 represents a critical heap-based buffer overflow in the FreeType font rendering library that affects multiple software products including Mozilla Firefox Mobile. This issue stems from inadequate input validation within the font parsing mechanism, specifically when processing crafted glyph-outline data contained in font files. The flaw exists in FreeType versions prior to 2.4.9 and has significant implications for mobile and desktop applications that rely on this widely-used font rendering component. The vulnerability manifests when the library attempts to write data to heap memory locations without proper bounds checking, creating opportunities for memory corruption that can be exploited by malicious actors.
The technical exploitation of this vulnerability occurs through the manipulation of font files containing specially crafted glyph-outline data that triggers an invalid heap write operation. When FreeType processes these malformed font structures, it fails to validate the size and boundaries of the data being written to memory, leading to heap corruption that can result in arbitrary code execution or denial of service conditions. This type of vulnerability falls under the CWE-122 category of heap-based buffer overflow, which is classified as a serious memory safety issue that can compromise system integrity. The attack vector involves delivering a malicious font file to a vulnerable application, where the font rendering process triggers the exploitable condition during normal operation.
The operational impact of CVE-2012-1142 extends beyond simple denial of service to potentially enable remote code execution, making it particularly dangerous in mobile environments where users frequently encounter untrusted font content. Mobile browsers like Firefox Mobile were especially vulnerable since they relied on FreeType for font rendering and had not yet implemented the necessary security patches. The vulnerability affects not only Firefox Mobile but also any other software products that utilize FreeType versions prior to 2.4.9, creating a widespread attack surface across various applications. This type of vulnerability aligns with ATT&CK technique T1059.007 for command and script interpreter execution, as successful exploitation could lead to arbitrary code execution on the target system.
Mitigation strategies for this vulnerability require immediate patching of FreeType libraries to version 2.4.9 or later, which includes proper input validation and bounds checking for glyph-outline data processing. System administrators should also implement font filtering mechanisms that restrict the types of font files allowed in vulnerable applications, particularly in mobile environments where users may encounter untrusted content. Additionally, applications should employ memory safety features such as stack canaries, address space layout randomization, and data execution prevention to reduce the effectiveness of potential exploitation attempts. Organizations should also consider implementing network-based security controls that can detect and block malicious font content before it reaches vulnerable applications, as outlined in the MITRE ATT&CK framework's approach to defending against software supply chain attacks and privilege escalation techniques.