CVE-2004-0083 in Solaris
Summary
by MITRE
Buffer overflow in ReadFontAlias from dirfile.c of XFree86 4.1.0 through 4.3.0 allows local users and remote attackers to execute arbitrary code via a font alias file (font.alias) with a long token, a different vulnerability than CVE-2004-0084 and CVE-2004-0106.
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Analysis
by VulDB Data Team • 12/17/2024
The vulnerability described in CVE-2004-0083 represents a critical buffer overflow flaw within the XFree86 graphics subsystem that affects versions 4.1.0 through 4.3.0. This issue resides in the ReadFontAlias function located in the dirfile.c source file, which processes font alias configuration files during X server initialization. The vulnerability manifests when the system encounters a font.alias file containing an excessively long token, creating a condition where user-supplied input exceeds the allocated buffer space. This particular flaw operates at the core level of the X Window System implementation, making it particularly dangerous as it can be exploited by both local users and remote attackers, thereby broadening its potential attack surface significantly.
The technical implementation of this buffer overflow stems from inadequate input validation within the font alias parsing routine. When the ReadFontAlias function processes font.alias files, it fails to properly bounds-check the length of tokens read from these configuration files before copying them into fixed-size buffers. This classic programming error allows attackers to craft malicious font.alias files containing oversized token sequences that overwrite adjacent memory locations. The vulnerability specifically aligns with CWE-121, which categorizes buffer overflow conditions where insufficient boundary checking permits writing beyond allocated buffer space. The flaw operates at the application level within the X server process, which typically runs with elevated privileges, making successful exploitation potentially catastrophic for system integrity and security.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with the capability to gain unauthorized access to systems running affected XFree86 versions. Local users can exploit this vulnerability to elevate their privileges or execute arbitrary code within the context of the X server process, while remote attackers can leverage it through network-based attacks if the X server is configured to accept remote connections. The attack vector is particularly concerning because font alias files are commonly used in X server configurations and can be manipulated through various legitimate system administration activities, making the exploitation more隐蔽 and harder to detect. According to ATT&CK framework, this vulnerability maps to T1059.007 for execution through command and scripting interpreter, and T1068 for privilege escalation, making it a significant threat in both local and remote attack scenarios.
Mitigation strategies for CVE-2004-0083 require immediate implementation of several defensive measures. System administrators should upgrade to XFree86 versions 4.3.1 or later, where the buffer overflow has been patched through proper bounds checking and input validation. Additionally, implementing strict file access controls on font.alias files can prevent unauthorized modification of these critical configuration files. The principle of least privilege should be enforced by ensuring that X server processes run with minimal required permissions, and regular security audits should monitor for potentially malicious font alias files. Network segmentation and firewall rules can help limit exposure to remote attacks by restricting access to X server ports. Organizations should also consider implementing intrusion detection systems to monitor for unusual font file modifications and maintain comprehensive backup procedures to quickly restore system configurations in case of successful exploitation attempts.