CVE-2011-0408 in libpng
Summary
by MITRE
pngrtran.c in libpng 1.5.x before 1.5.1 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted palette-based PNG image that triggers a buffer overflow, related to the png_do_expand_palette function, the png_do_rgb_to_gray function, and an integer underflow. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 01/19/2025
The vulnerability identified as CVE-2011-0408 represents a critical security flaw within the libpng library version 1.5.x prior to 1.5.1, specifically affecting the handling of palette-based PNG images. This vulnerability stems from improper bounds checking and integer overflow conditions within the png_do_expand_palette and png_do_rgb_to_gray functions, creating a scenario where maliciously crafted PNG files can trigger buffer overflow conditions that lead to application instability or potential code execution.
The technical root cause of this vulnerability lies in the insufficient validation of image data parameters during the PNG decoding process. When libpng processes palette-based images, the png_do_expand_palette function attempts to expand the color palette into a full RGB representation, while the png_do_rgb_to_gray function handles conversions between color spaces. These functions fail to properly validate the size parameters of the palette data, creating opportunities for integer underflow conditions that can result in negative array indices or invalid memory access patterns. The combination of these flaws allows attackers to craft PNG files with malformed palette data that, when processed by vulnerable libpng versions, can cause memory corruption.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable remote code execution, making it particularly dangerous for web applications and services that process user-uploaded images. When an application using the vulnerable libpng library encounters a specially crafted palette-based PNG image, the buffer overflow conditions can cause the application to crash or potentially allow attackers to execute arbitrary code within the application's memory space. This risk is amplified in environments where applications process untrusted image data from web users, as attackers can exploit this vulnerability through web interfaces without requiring local system access. The vulnerability affects a wide range of applications including web browsers, image processing software, and any system that relies on libpng for PNG image handling.
Mitigation strategies for this vulnerability require immediate patching of affected libpng installations to version 1.5.1 or later, which includes proper bounds checking and integer overflow protection mechanisms. System administrators should also implement image validation measures such as MIME type checking, file size limits, and pre-processing of uploaded images through trusted image processing libraries to prevent exploitation. Additionally, network segmentation and application sandboxing can help limit the potential impact of successful exploitation attempts. The vulnerability aligns with CWE-129, which addresses improper validation of array indices, and CWE-190, which covers integer overflow conditions, while potentially mapping to ATT&CK technique T1203 for process injection and T1499 for network denial of service depending on the exploitation method used.
Organizations should conduct comprehensive vulnerability assessments to identify all systems running vulnerable libpng versions and prioritize patch deployment across their infrastructure. Regular security updates and vulnerability management processes should include monitoring for similar issues in other image processing libraries and maintaining up-to-date security patches for all third-party components. The vulnerability demonstrates the importance of proper input validation and bounds checking in multimedia processing libraries, as these components often handle untrusted data from external sources and require robust protection against malformed input that could lead to memory corruption and arbitrary code execution.