CVE-2021-21808 in ImageGear
Summary
by MITRE • 06/11/2021
A memory corruption vulnerability exists in the PNG png_palette_process functionality of Accusoft ImageGear 19.9. A specially crafted malformed file can lead to a heap buffer overflow. An attacker can provide malicious inputs to trigger this vulnerability.
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Analysis
by VulDB Data Team • 06/14/2021
The vulnerability identified as CVE-2021-21808 represents a critical memory corruption issue within the Accusoft ImageGear 19.9 image processing library, specifically affecting the png_palette_process functionality. This flaw resides in the handling of portable network graphics files and demonstrates a classic heap buffer overflow condition that can be exploited through carefully crafted malicious input files. The vulnerability stems from inadequate bounds checking during the processing of palette information within png image files, creating an opportunity for attackers to manipulate memory layout and potentially execute arbitrary code.
The technical implementation of this vulnerability occurs when the ImageGear library processes malformed png files containing crafted palette data. During the png_palette_process function execution, the software fails to properly validate the size and structure of palette information before attempting to copy or manipulate data into allocated memory buffers. This insufficient input validation creates a condition where attacker-controlled data can exceed the allocated buffer boundaries, leading to memory corruption that may result in application crashes, data corruption, or more severe exploitation opportunities. The flaw operates at the intersection of buffer management and image file parsing, making it particularly dangerous in environments where image processing libraries handle untrusted input from external sources.
From an operational perspective, this vulnerability presents significant risk to systems that rely on Accusoft ImageGear for image processing tasks, particularly those handling user-uploaded content or processing images from untrusted sources. The heap buffer overflow can lead to denial of service conditions where applications crash or become unresponsive, while in more sophisticated attack scenarios, the memory corruption could potentially be leveraged to achieve arbitrary code execution. The vulnerability is especially concerning in web applications, content management systems, and document processing platforms where users might upload png files without proper sanitization. Security analysts should consider this vulnerability as a potential entry point for privilege escalation attacks, particularly when the affected software runs with elevated privileges.
Mitigation strategies for CVE-2021-21808 should prioritize immediate patching of the Accusoft ImageGear library to version 19.10 or later, which contains the necessary fixes for the heap buffer overflow condition. Organizations should implement comprehensive input validation and sanitization measures for all png file processing, including mandatory file format verification and size restriction checks before any image processing occurs. Network segmentation and application whitelisting can help limit the impact of potential exploitation attempts, while monitoring systems should be configured to detect unusual memory allocation patterns or application crashes that may indicate exploitation attempts. The vulnerability aligns with CWE-121 heap-based buffer overflow classification and represents a potential technique within the attack chain described by MITRE ATT&CK framework under the T1059.007 execution technique, specifically targeting application-level vulnerabilities in image processing components.