CVE-2003-0730 in XFree86
Summary
by MITRE
Multiple integer overflows in the font libraries for XFree86 4.3.0 allow local or remote attackers to cause a denial of service or execute arbitrary code via heap-based and stack-based buffer overflow attacks.
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Analysis
by VulDB Data Team • 06/26/2019
The vulnerability described in CVE-2003-0730 represents a critical security flaw affecting XFree86 version 4.3.0 font libraries, specifically targeting integer overflows within the rendering and processing components. This issue stems from inadequate input validation and boundary checking mechanisms that fail to properly handle malformed font data, creating exploitable conditions that can be leveraged by both local and remote attackers. The vulnerability exists in the fundamental font processing libraries that handle various font formats including TrueType and PostScript fonts, which are essential components for graphical user interface rendering across Unix-like systems and Linux distributions.
The technical implementation of this vulnerability manifests through multiple integer overflow conditions that occur during font processing operations, particularly when handling font metrics and character glyph data. These overflows result in heap-based and stack-based buffer overflow conditions that can be systematically exploited to manipulate program execution flow. When the font libraries process malformed or specially crafted font files, the integer overflows cause memory corruption that can be leveraged to either crash the affected application or potentially execute arbitrary code with the privileges of the running process. The vulnerability specifically targets the memory management routines responsible for allocating buffers based on computed font dimensions, where integer overflow results in insufficient buffer allocation that subsequent writes can overflow.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass potential privilege escalation and system compromise. Local attackers can exploit these conditions to gain elevated privileges on systems running vulnerable XFree86 implementations, while remote attackers can potentially exploit the same vulnerabilities through network-based font delivery mechanisms. The widespread adoption of XFree86 in enterprise and desktop environments meant that exploitation could affect numerous systems simultaneously, particularly those running graphical applications that rely on font rendering capabilities. The vulnerability affects not just the X server itself but also applications that depend on the underlying font libraries, amplifying the potential attack surface significantly.
Mitigation strategies for CVE-2003-0730 require immediate system updates and patches to address the underlying integer overflow conditions in the XFree86 font libraries. System administrators should prioritize applying security patches from vendor sources and implementing network segmentation to limit exposure to potential remote exploitation attempts. Additional defensive measures include implementing proper input validation for font data, utilizing privilege separation mechanisms, and deploying intrusion detection systems to monitor for exploitation attempts. The vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions, and represents a classic example of how buffer overflow vulnerabilities can be exploited to achieve arbitrary code execution. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and code injection, with potential lateral movement capabilities through compromised graphical interfaces. Organizations should also consider implementing application whitelisting and monitoring for unusual font processing activities that could indicate exploitation attempts.