CVE-2010-4259 in FontForge
Summary
by MITRE
Stack-based buffer overflow in FontForge 20100501 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a long CHARSET_REGISTRY header in a BDF font file.
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Analysis
by VulDB Data Team • 10/06/2024
The vulnerability identified as CVE-2010-4259 represents a critical stack-based buffer overflow flaw discovered in FontForge version 20100501, specifically affecting the handling of BDF (Bitmap Distribution Format) font files. This issue arises from insufficient input validation when processing the CHARSET_REGISTRY header field within BDF font files, creating a scenario where maliciously crafted font files can trigger unpredictable behavior in the application. The vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations on the program stack.
The technical exploitation of this vulnerability occurs when FontForge attempts to parse a BDF font file containing an excessively long CHARSET_REGISTRY header value. The application's parsing routine fails to properly validate the length of this header field, allowing an attacker to provide input that exceeds the allocated stack buffer space. When the parsing routine executes, it writes data beyond the boundaries of the intended buffer, causing memory corruption that results in application instability. This memory corruption can manifest as either an application crash leading to denial of service or potentially more severe consequences including arbitrary code execution, depending on the specific memory layout and the attacker's control over the overflowed data.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it represents a potential vector for remote code execution within systems that process untrusted font files. Attackers can leverage this flaw by delivering malicious BDF font files through various attack vectors including email attachments, web downloads, or compromised software distribution channels. The vulnerability affects systems where FontForge is installed and actively processes font files, making it particularly dangerous in environments where font rendering is critical or where users may encounter untrusted font content. This flaw particularly impacts desktop environments, graphic design applications, and systems that automatically process font files from external sources.
Mitigation strategies for CVE-2010-4259 should focus on immediate remediation through software updates to FontForge versions that address the buffer overflow condition. Organizations should implement strict input validation measures and consider deploying application whitelisting solutions that restrict font file processing to trusted sources only. Network-based defenses can include filtering BDF font files at network boundaries and implementing sandboxing techniques for font processing operations. The vulnerability demonstrates the importance of proper bounds checking in memory management operations and aligns with ATT&CK technique T1203, which covers exploitation of input validation flaws in applications. System administrators should also consider implementing automated patch management processes to ensure timely deployment of security updates and maintain comprehensive monitoring for potential exploitation attempts targeting this vulnerability.