CVE-2012-1132 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 dictionary data in a Type 1 font.
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Analysis
by VulDB Data Team • 05/01/2018
The vulnerability identified as CVE-2012-1132 represents a critical heap-based buffer overflow flaw within the FreeType font rendering library that affects multiple applications including Mozilla Firefox Mobile. This issue stems from inadequate input validation when processing Type 1 font files, specifically during the handling of dictionary data structures. The vulnerability has been classified under CWE-125 as an out-of-bounds read condition, which can lead to unpredictable behavior and potential code execution. The flaw manifests when FreeType attempts to parse malformed dictionary entries within Type 1 font files, causing the library to read from invalid memory locations that may contain sensitive data or trigger memory corruption. This particular vulnerability impacts Firefox Mobile versions prior to 10.0.4 and other software products that rely on FreeType for font rendering operations, making it a widespread concern across mobile and desktop platforms that utilize this font engine. The attack vector involves remote code execution through maliciously crafted font files that can be delivered via web content or downloaded attachments, presenting a significant threat to user security and system integrity.
The technical exploitation of this vulnerability occurs when a victim's system processes a specially crafted Type 1 font file containing malformed dictionary data. FreeType's parser fails to properly validate the bounds of dictionary entries, leading to an invalid heap read operation that can cause memory corruption and potentially allow attackers to execute arbitrary code with the privileges of the affected application. This type of vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1203 for exploitation for execution, as it enables attackers to gain unauthorized code execution capabilities. The memory corruption aspect of this vulnerability can manifest in various ways including application crashes, data leakage, or complete system compromise depending on the execution environment and memory layout. The vulnerability's impact is particularly severe because Type 1 fonts are commonly used in web content and document processing, making exploitation possible through routine browsing activities or document opening operations. Security researchers have noted that the flaw can be triggered through both direct font file processing and indirect means such as web-based content rendering, significantly expanding the attack surface.
The operational impact of CVE-2012-1132 extends beyond simple denial of service to encompass potential full system compromise, making it a critical security concern for organizations and individual users. Mobile platforms are especially vulnerable due to the limited security controls and the prevalence of web-based content consumption in mobile environments. The vulnerability can be exploited in various contexts including malicious websites, email attachments, and document files that contain embedded fonts, creating multiple attack vectors for threat actors. Organizations relying on FreeType-based applications must consider the risk of privilege escalation and data breaches when this vulnerability remains unpatched. The exploitability of this vulnerability is enhanced by the fact that many applications automatically process fonts without user intervention, meaning users can be compromised simply by visiting malicious websites or opening infected documents. Security professionals should note that this vulnerability represents a classic example of a heap-based buffer overflow that can be leveraged for advanced persistent threat campaigns, particularly in targeted attacks against high-value targets. The vulnerability's classification as a remote code execution flaw means that exploitation does not require local access to the system, making it particularly dangerous in networked environments.
Mitigation strategies for CVE-2012-1132 primarily focus on immediate patch deployment and application updates to ensure that affected versions of FreeType and dependent applications are updated to patched versions. The most effective immediate remediation involves updating to FreeType version 2.4.9 or later, which contains the necessary fixes for the heap read overflow conditions. Organizations should implement comprehensive patch management procedures to ensure all affected applications are updated promptly, including Firefox Mobile, web browsers, and any other software that utilizes FreeType for font rendering. Additional defensive measures include implementing application whitelisting policies, restricting font file processing in web applications, and deploying network-based intrusion detection systems that can identify and block malicious font content. Security teams should also consider implementing sandboxing mechanisms for font processing operations to limit the potential impact of successful exploitation attempts. The vulnerability highlights the importance of proper input validation and bounds checking in font processing libraries, emphasizing the need for regular security audits of core system components. Organizations should also establish monitoring procedures to detect unusual font processing activities that may indicate exploitation attempts, particularly in environments where web content is frequently accessed or where document processing is common. Regular security assessments and vulnerability scanning should include checks for outdated FreeType installations to prevent this vulnerability from being exploited in compromised environments.