CVE-2011-0034 in Windows
Summary
by MITRE
Stack-based buffer overflow in the OpenType Compact Font Format (aka OTF or CFF) driver in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows remote attackers to execute arbitrary code via crafted parameter values in an OpenType font, aka "OpenType Font Stack Overflow Vulnerability."
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Analysis
by VulDB Data Team • 01/19/2025
The vulnerability identified as CVE-2011-0034 represents a critical stack-based buffer overflow flaw within Microsoft Windows operating systems' handling of OpenType Compact Font Format fonts. This issue affects a wide range of Windows versions including Windows XP Service Pack 2 and 3, Windows Server 2003 Service Pack 2, Windows Vista Service Pack 1 and 2, Windows Server 2008 in various service pack configurations, and Windows 7. The flaw specifically resides in the OpenType Compact Font Format driver which processes font files for display purposes, making it a prime target for exploitation through malicious font content.
The technical implementation of this vulnerability stems from inadequate input validation within the CFF font processing component of Windows GDI+ graphics subsystem. When a Windows system processes a specially crafted OpenType font file containing malformed parameter values, the application fails to properly bounds-check buffer allocations during font parsing operations. This allows an attacker to overwrite adjacent memory locations on the stack, potentially corrupting critical program execution data including return addresses and function pointers. The vulnerability manifests when the system attempts to render or process font glyphs from a maliciously constructed font file, making it particularly dangerous as it can be triggered through normal font rendering operations.
The operational impact of this vulnerability extends far beyond simple code execution, representing a significant threat to system integrity and user security across enterprise and consumer environments. Attackers can leverage this flaw to gain arbitrary code execution privileges on vulnerable systems, potentially escalating to system compromise or privilege escalation attacks. The vulnerability's remote exploitability means that malicious actors can deliver payloads through various attack vectors including email attachments, web downloads, or network shares without requiring user interaction beyond viewing or printing the affected font. This makes it particularly dangerous in enterprise environments where font files might be automatically processed during document rendering or system operations. The attack surface is extensive given that font files are commonly encountered in legitimate business operations, making detection and prevention challenging.
Microsoft addressed this vulnerability through security updates released in March 2011 as part of their regular security bulletin cycle, with the patch specifically targeting the buffer overflow conditions in the OpenType Compact Font Format driver. Organizations should prioritize deployment of these security updates across all affected Windows systems to mitigate the risk of exploitation. Additional mitigation strategies include implementing font filtering policies, disabling automatic font rendering for untrusted sources, and employing application whitelisting solutions to prevent execution of malicious font files. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow and follows ATT&CK technique T1059.007 for execution through font files, representing a classic example of how graphics rendering components can serve as attack vectors in modern operating systems. Organizations should also consider implementing network-based intrusion detection systems to monitor for exploitation attempts targeting this specific vulnerability.