CVE-2004-0768 in libpng
Summary
by MITRE
libpng 1.2.5 and earlier does not properly calculate certain buffer offsets, which could allow remote attackers to execute arbitrary code via a buffer overflow attack.
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Analysis
by VulDB Data Team • 06/02/2019
The vulnerability identified as CVE-2004-0768 represents a critical buffer overflow flaw within the libpng library version 1.2.5 and earlier. This issue stems from improper calculation of buffer offsets during the processing of png image files, creating a scenario where maliciously crafted image data can trigger memory corruption. The libpng library serves as a fundamental component for handling png image format operations across numerous applications and operating systems, making this vulnerability particularly dangerous as it can be exploited through various attack vectors that involve png file processing. The flaw occurs during the parsing of png image headers and data structures, where insufficient bounds checking allows attackers to manipulate memory layout through carefully constructed malicious input.
The technical implementation of this vulnerability involves the manipulation of png image data structures that are processed by the vulnerable libpng library. When the library encounters a specially crafted png file, the improper buffer offset calculations cause the program to write data beyond the allocated memory boundaries. This memory corruption can occur during various stages of png file processing including chunk parsing, data decompression, or color transformation operations. The buffer overflow typically manifests when the library attempts to read or write data to memory locations that are not properly allocated for the intended operation. Attackers can exploit this by creating png files with maliciously constructed data that causes the library to perform out-of-bounds memory operations, potentially leading to arbitrary code execution.
The operational impact of CVE-2004-0768 extends across numerous software ecosystems that rely on libpng for image processing functionality. Applications including web browsers, image viewers, graphic design software, and server applications that handle user-uploaded png files become vulnerable to remote code execution attacks. This vulnerability particularly affects web-based applications where users can upload png images, as attackers can craft malicious files that exploit the buffer overflow when the server processes these images. The attack surface is extensive given that libpng is integrated into many operating systems, web browsers, content management systems, and enterprise applications, making successful exploitation potentially widespread and difficult to contain. The vulnerability can be leveraged for privilege escalation, system compromise, or denial of service attacks depending on the specific implementation and execution environment.
Mitigation strategies for CVE-2004-0768 primarily focus on immediate library updates and code-level defenses. Organizations should prioritize upgrading to libpng versions 1.2.6 or later, which contain the necessary patches to address the buffer overflow calculations. System administrators must conduct comprehensive vulnerability assessments to identify all applications using vulnerable libpng versions and implement patch management procedures to ensure timely updates. Additional defensive measures include implementing input validation and sanitization for all png file processing operations, deploying network-based intrusion detection systems to monitor for malicious png file transfers, and configuring applications to limit file size and type restrictions when processing user uploads. The vulnerability aligns with CWE-121 and CWE-125 categories related to stack-based and heap-based buffer overflow conditions, and represents a classic example of ATT&CK technique T1203 for exploitation of software vulnerabilities. Organizations should also consider implementing application sandboxing and memory protection mechanisms to limit the potential impact of successful exploitation attempts.