CVE-2012-1127 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 crafted glyph or bitmap data in a BDF font.
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Analysis
by VulDB Data Team • 05/01/2018
The vulnerability identified as CVE-2012-1127 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 resides in the handling of BDF (Bitmap Distribution Format) font files and demonstrates how font processing components can become attack vectors for remote code execution or denial of service conditions. The flaw specifically manifests when FreeType processes malformed glyph or bitmap data contained within BDF font files, creating opportunities for attackers to manipulate memory structures through carefully crafted font content. The vulnerability is classified under CWE-125 as an out-of-bounds read condition, which can lead to unpredictable behavior and potential exploitation. When exploited, this vulnerability can result in invalid heap read operations that may trigger memory corruption and ultimately allow for arbitrary code execution on vulnerable systems. The impact extends beyond just Firefox Mobile to any application that utilizes FreeType version prior to 2.4.9 for font rendering operations, making it a widespread concern across multiple software platforms and operating systems.
The technical exploitation of this vulnerability involves crafting malicious BDF font files that contain malformed glyph or bitmap data designed to trigger buffer overflow conditions within FreeType's memory management routines. Attackers can leverage this flaw by delivering specially constructed font files through web content, email attachments, or other delivery mechanisms that cause vulnerable applications to process the malicious font data. The vulnerability's exploitation pathway aligns with ATT&CK technique T1068 which describes the use of privilege escalation or code execution through software vulnerabilities. When FreeType attempts to parse the malformed BDF font data, it fails to properly validate the size and structure of the glyph or bitmap information, leading to memory corruption that can be manipulated to execute arbitrary code. The heap-based nature of the vulnerability means that attackers can potentially overwrite critical memory locations or manipulate heap metadata to achieve code execution, while the invalid heap read operations can cause applications to crash or behave unpredictably. This type of vulnerability is particularly dangerous because it can be triggered through web-based content, making it accessible to attackers who do not require physical access to target systems.
The operational impact of CVE-2012-1127 extends significantly across mobile and desktop environments where FreeType is integrated into font rendering pipelines, particularly affecting mobile browsers and applications that process external font content. Organizations deploying vulnerable versions of Firefox Mobile or other affected applications face substantial risk of remote code execution attacks that could compromise user devices and potentially lead to data breaches or further system compromise. The vulnerability's presence in widely used software components means that successful exploitation could affect thousands of devices and users simultaneously, particularly in mobile environments where users may encounter malicious font content through web browsing or email. Security researchers have documented that this vulnerability can be triggered through simple web page loads when the affected browser processes BDF font files, making it an attractive target for automated exploitation campaigns. The vulnerability's potential for causing denial of service conditions means that even successful exploitation without code execution could render affected applications unusable, creating significant disruption to user activities and potentially enabling persistent denial of service attacks.
Mitigation strategies for CVE-2012-1127 primarily focus on updating to patched versions of FreeType and affected applications, with Mozilla Firefox Mobile users needing to upgrade to version 10.0.4 or later. System administrators should implement immediate patch management procedures to address this vulnerability across all affected systems, particularly those handling external font content or web browsing activities. Additional protective measures include implementing content filtering solutions that can detect and block potentially malicious font files, disabling automatic font downloading in web browsers, and configuring applications to use safe font rendering modes that limit the processing of external font content. Organizations should also consider implementing network-based intrusion detection systems that can identify exploitation attempts targeting this vulnerability. The remediation process should include thorough testing of patched versions to ensure that the updates do not introduce compatibility issues with legitimate font processing requirements. Security monitoring should be enhanced to detect unusual font processing activities that might indicate exploitation attempts, and incident response procedures should be updated to address potential exploitation of this vulnerability in the event of successful attacks. Regular vulnerability assessments should be conducted to identify other potentially affected components that might be utilizing vulnerable versions of FreeType or similar font processing libraries.