CVE-2019-5076 in ImageGear
Summary
by MITRE
An exploitable out-of-bounds write vulnerability exists in the igcore19d.dll PNG header-parser of the Accusoft ImageGear 19.3.0 library. A specially crafted PNG file can cause an out-of-bounds write, resulting in a remote code execution. An attacker needs to provide a malformed file to the viction to trigger the vulnerability.
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Analysis
by VulDB Data Team • 03/07/2024
The vulnerability identified as CVE-2019-5076 represents a critical out-of-bounds write flaw within the Accusoft ImageGear 19.3.0 library, specifically within the igcore19d.dll component responsible for parsing PNG image headers. This vulnerability resides in the image processing pipeline where the library fails to properly validate the dimensions and structure of PNG files during header parsing operations. The flaw manifests when the parser encounters a malformed PNG file that contains crafted metadata or header values that exceed the expected buffer boundaries, creating a condition where memory writes occur beyond the allocated buffer space. The vulnerability is classified as an out-of-bounds write according to CWE-787, which falls under the broader category of memory safety issues that can lead to arbitrary code execution. The precise technical mechanism involves the PNG parser not adequately validating the image dimensions or color palette specifications within the PNG header structure, allowing attackers to manipulate the parsing logic through maliciously constructed image files that cause buffer overflow conditions in the memory allocation.
The operational impact of this vulnerability extends significantly beyond simple denial-of-service scenarios, as it enables remote code execution capabilities that can be exploited by malicious actors without requiring local system access. When a victim application processes a specially crafted PNG file through the vulnerable ImageGear library, the out-of-bounds write can overwrite adjacent memory locations, potentially corrupting critical program structures, function pointers, or control flow data. This memory corruption can be leveraged by attackers to redirect program execution to malicious code injected into the process memory space, effectively achieving remote code execution. The vulnerability is particularly concerning because it operates at the image parsing layer where applications typically process untrusted user input, making it a prime target for exploitation in web applications, email clients, or any software that handles image file processing. The attack vector requires only that an attacker convince a victim to open or process the malicious PNG file through an application that utilizes the vulnerable ImageGear library, making it highly accessible for widespread exploitation.
Mitigation strategies for CVE-2019-5076 must address both immediate defensive measures and long-term architectural improvements to prevent similar vulnerabilities from occurring in image processing libraries. Organizations should prioritize updating to the latest versions of the Accusoft ImageGear library where the vulnerability has been patched, as the vendor has released fixes that include proper bounds checking and input validation for PNG header parsing operations. Additionally, implementing defensive programming practices such as bounds checking, stack canaries, and address space layout randomization can significantly reduce the exploitability of similar vulnerabilities. The vulnerability demonstrates the importance of adhering to secure coding guidelines and following the principle of least privilege in image processing applications, where input validation should occur at multiple layers of the processing pipeline. Security practitioners should also consider implementing network-based intrusion detection systems that can identify suspicious image file patterns and monitor for exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to the T1059.007 technique for command and control through remote access tools, as successful exploitation would provide attackers with persistent remote access to affected systems. The vulnerability also aligns with T1203, which covers exploitation for privilege escalation through memory corruption techniques, highlighting the need for comprehensive patch management and application hardening strategies to prevent unauthorized access to target systems.