CVE-2011-0202 in Mac OS X
Summary
by MITRE
Integer overflow in CoreGraphics in Apple Mac OS X before 10.6.8 allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted embedded Type 1 font in a PDF document.
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Analysis
by VulDB Data Team • 11/13/2021
The vulnerability described in CVE-2011-0202 represents a critical integer overflow flaw within Apple's CoreGraphics framework affecting Mac OS X versions prior to 10.6.8. This issue specifically manifests when processing embedded Type 1 fonts within PDF documents, creating a pathway for remote attackers to potentially execute arbitrary code or induce application crashes. The vulnerability stems from insufficient input validation and boundary checking during font parsing operations, where the system fails to properly handle oversized or malformed font data structures that could lead to memory corruption.
CoreGraphics serves as a fundamental graphics rendering framework in macOS, responsible for processing and displaying graphical content including fonts, images, and vector graphics. When a PDF document containing a specially crafted Type 1 font is opened, the framework attempts to parse the font data and allocate memory based on calculated dimensions. The integer overflow occurs during these calculations, where the system performs arithmetic operations that exceed the maximum representable value for the integer data type, resulting in unexpected behavior. This flaw operates at the intersection of software security and graphics processing, leveraging the legitimate font embedding capabilities of PDF documents to deliver malicious payloads.
The operational impact of this vulnerability extends beyond simple application crashes to potentially enable full system compromise through arbitrary code execution. Attackers can craft PDF documents with malformed Type 1 fonts that trigger the integer overflow condition when opened by vulnerable systems, leading to memory corruption that may be exploited to redirect program execution flow. The remote exploitation capability means attackers do not require physical access to target systems, making this vulnerability particularly dangerous in environments where users regularly open PDF documents from untrusted sources. This vulnerability aligns with CWE-190, which describes integer overflow conditions, and represents a classic example of how graphics processing libraries can become attack vectors when insufficient input sanitization is implemented.
From a threat modeling perspective, this vulnerability demonstrates how seemingly benign document processing functionality can be weaponized through carefully crafted inputs. The attack surface is broad since PDF documents are commonly shared across networks and email systems, making the exploitation vector highly accessible to threat actors. The vulnerability's classification under the ATT&CK framework would fall within the T1059.007 technique for command and script interpreter, as successful exploitation could enable attackers to execute arbitrary commands on affected systems. Organizations should implement immediate mitigations including updating to Mac OS X 10.6.8 or later, deploying PDF security measures, and restricting PDF document handling in high-security environments. Additionally, network-based security controls such as web application firewalls and email filtering systems should be configured to scan and block suspicious PDF content that may contain embedded malicious fonts, while also monitoring for indicators of compromise related to this specific vulnerability.