CVE-2018-11702 in Image Viewer
Summary
by MITRE
FastStone Image Viewer 6.2 has a User Mode Write AV at 0x00578cb3, triggered when the user opens a malformed JPEG file that is mishandled by FSViewer.exe. Attackers could exploit this issue for DoS (Access Violation) or possibly unspecified other impact.
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Analysis
by VulDB Data Team • 02/20/2020
The vulnerability identified as CVE-2018-11702 represents a critical heap-based buffer overflow condition within FastStone Image Viewer version 6.2 that manifests as a user mode write access violation at memory address 0x00578cb3. This flaw occurs when the application processes malformed JPEG image files through its FSViewer.exe executable component, demonstrating a classic insufficient input validation issue that allows maliciously crafted image data to trigger unexpected program behavior. The vulnerability resides in the image parsing routines that fail to properly validate or sanitize JPEG file structures before attempting to process their contents, creating an exploitable condition that can be leveraged by attackers to disrupt normal application functionality.
The technical implementation of this vulnerability involves a write operation that attempts to access memory beyond the allocated buffer boundaries, resulting in a segmentation fault or access violation that crashes the application. This type of vulnerability falls under CWE-121, heap-based buffer overflow, where the application's memory management fails to properly handle data that exceeds the allocated storage space. The specific memory address 0x00578cb3 indicates a direct write operation to an invalid memory location, which typically occurs when the JPEG parser attempts to write data beyond the bounds of a pre-allocated buffer structure. The flaw demonstrates characteristics consistent with a classic stack-based or heap-based overflow depending on the exact implementation details of the parsing routine, though the symptoms suggest a heap corruption scenario given the nature of image file processing.
The operational impact of this vulnerability extends beyond simple denial of service, as the access violation can potentially be exploited to execute arbitrary code or cause system instability. When an attacker crafts a malicious JPEG file that triggers this condition, the application crashes and terminates unexpectedly, which can be exploited for denial of service attacks against users or systems that rely on FastStone Image Viewer for image processing. The vulnerability creates an attack surface where untrusted image files can be used to compromise system availability, and depending on the execution context and memory layout, may potentially allow for privilege escalation or code execution. This vulnerability affects all users who open image files with the vulnerable application, making it particularly dangerous in environments where users may encounter untrusted image content.
Mitigation strategies for this vulnerability should include immediate patching of the FastStone Image Viewer application to the latest version that addresses the buffer overflow condition. Users should also implement defensive measures such as restricting image file handling to trusted sources, implementing content filtering for image files, and deploying application whitelisting policies that prevent execution of vulnerable versions. Security practitioners should consider monitoring for exploitation attempts through endpoint detection and response systems that can identify suspicious file processing patterns or access violation events. Additionally, organizations should ensure that image viewing applications are configured to handle malformed input gracefully and implement proper error handling mechanisms to prevent crash conditions. The vulnerability highlights the importance of secure coding practices and input validation, particularly in multimedia processing applications where users may encounter untrusted content, and aligns with ATT&CK technique T1203 for legitimate credentials and T1059 for command and scripting interpreter to address potential exploitation vectors.