CVE-2012-1128 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 (NULL pointer dereference 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-2012-1128 represents a critical security flaw in the FreeType font rendering library that affects multiple applications including Mozilla Firefox Mobile. This issue stems from inadequate input validation within the font parsing mechanism, specifically when processing specially crafted TrueType font files. The vulnerability exists in FreeType versions prior to 2.4.9 and has significant implications for mobile browser security, as it was present in Firefox Mobile versions before 10.0.4. The flaw manifests as a NULL pointer dereference condition that can lead to system instability and potentially arbitrary code execution, making it a severe concern for mobile device security.
The technical implementation of this vulnerability occurs during the parsing of TrueType font files where the FreeType library fails to properly validate font structure elements before attempting to access memory locations. When a maliciously crafted font file is processed, the library encounters unexpected data structures that result in a NULL pointer dereference, causing the application to crash or potentially allowing an attacker to manipulate memory contents. This type of vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference conditions, and aligns with ATT&CK technique T1059.007 for abuse of system services through malformed input processing. The memory corruption aspect of this vulnerability demonstrates the potential for more severe exploitation, as attackers could potentially manipulate the program's execution flow through carefully constructed font data.
The operational impact of CVE-2012-1128 extends beyond simple denial of service scenarios, as it creates potential entry points for more sophisticated attacks targeting mobile device users. Mobile browsers that utilize FreeType for font rendering become vulnerable to remote exploitation when users encounter maliciously crafted fonts in web content or downloaded materials. The vulnerability's presence in Firefox Mobile before version 10.0.4 meant that users were exposed to potential compromise through web browsing activities, particularly when visiting malicious websites or downloading content from untrusted sources. This type of vulnerability is particularly concerning in mobile environments where users may have limited ability to update their software frequently and where the attack surface includes both web browsing and email attachments.
Mitigation strategies for CVE-2012-1128 primarily involve updating to patched versions of FreeType library, specifically version 2.4.9 or later, and ensuring that affected applications like Firefox Mobile are updated to versions that incorporate these fixes. Organizations should implement proactive patch management policies that prioritize updates to font rendering libraries and browser applications, particularly in mobile environments where the attack surface is more constrained but potentially more dangerous. Additionally, implementing network-level protections such as web application firewalls and content filtering systems can help reduce exposure to malicious font files. Security monitoring should include detection of unusual font processing activities and memory corruption patterns that may indicate exploitation attempts. The vulnerability serves as a reminder of the importance of input validation in font processing libraries and demonstrates how seemingly benign components like font rendering can become critical attack vectors when not properly secured against malformed input.