CVE-2012-1144 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 a crafted TrueType font.
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Analysis
by VulDB Data Team • 04/13/2021
The vulnerability identified as CVE-2012-1144 represents a critical heap-based buffer overflow in the FreeType font rendering library that affects multiple software products including Mozilla Firefox Mobile versions prior to 10.0.4. This flaw resides in the handling of malformed TrueType font files and demonstrates the inherent risks associated with font processing components in web browsers and applications. The vulnerability stems from insufficient validation of font structure parameters during the parsing of TrueType font data, particularly when processing font tables that define glyph metrics and positioning information.
The technical implementation of this vulnerability involves a specific flaw in how FreeType processes certain font table entries, particularly within the font header and glyph data structures. When a maliciously crafted TrueType font is processed, the library fails to properly validate the size and structure of font tables, leading to an invalid heap write operation where the program attempts to write data beyond the allocated memory boundaries. This memory corruption occurs during the font rendering process when the application attempts to parse and display the malformed font, creating a condition that can be exploited to either crash the application or potentially execute arbitrary code. The flaw specifically affects the font table parsing logic where the program calculates offsets and sizes based on potentially malicious input without proper bounds checking.
From an operational perspective, this vulnerability presents a significant risk to mobile browser users and applications that rely on FreeType for font rendering. The attack vector is particularly dangerous because it can be triggered through normal web browsing activities when users encounter maliciously crafted fonts embedded in web pages or downloaded as attachments. The impact ranges from simple denial of service conditions where applications crash and require restart, to more severe scenarios where attackers could potentially execute arbitrary code with the privileges of the affected application. This vulnerability affects not only Firefox Mobile but also other software products that utilize FreeType, making it a widespread concern across the mobile and desktop computing landscape. The exploitation requires minimal user interaction beyond visiting a malicious website or opening a compromised document, making it particularly dangerous in mobile environments where users may have limited control over content filtering.
The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1059.007 for application execution through legitimate system processes. Organizations should implement immediate mitigations including updating to FreeType version 2.4.9 or later, which contains the necessary patches to validate font table structures properly. Additionally, browser vendors should ensure their font rendering components are updated and consider implementing additional sandboxing measures around font processing. The mitigation strategy should also include network-level filtering to block suspicious font files and regular security audits of font processing components. This vulnerability highlights the importance of proper input validation in font rendering libraries and demonstrates how seemingly benign components like font handling can become attack vectors in modern computing environments where users encounter diverse content sources.