CVE-2017-7962 in ImageWorsener
Summary
by MITRE
The iwgif_read_image function in imagew-gif.c in libimageworsener.a in ImageWorsener 1.3.0 allows remote attackers to cause a denial of service (divide-by-zero error and application crash) via a crafted file.
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Analysis
by VulDB Data Team • 12/01/2022
The vulnerability identified as CVE-2017-7962 represents a critical denial of service flaw within the ImageWorsener library version 1.3.0, specifically affecting the iwgif_read_image function in the imagew-gif.c module. This issue arises from insufficient input validation when processing specially crafted gif image files, creating a scenario where a malicious actor can deliberately trigger a divide-by-zero error that leads to application instability and complete crash. The flaw exists in the image processing pipeline where the library fails to properly validate mathematical operations during gif file parsing, particularly when encountering malformed dimension parameters within the gif structure.
The technical execution of this vulnerability occurs through the manipulation of gif file headers and metadata, specifically targeting the width and height values that are used in mathematical calculations during image decoding. When the iwgif_read_image function attempts to process a crafted gif file containing invalid dimension values, the division operation used for scaling or coordinate calculations results in a zero denominator, causing the application to terminate abruptly. This type of error falls under CWE-369, which categorizes divide-by-zero conditions as a fundamental arithmetic error that can lead to system instability and service disruption. The vulnerability demonstrates a classic lack of proper error handling and input sanitization in image processing libraries, where the software assumes valid mathematical inputs without proper validation checks.
From an operational perspective, this vulnerability presents a significant risk to systems that rely on ImageWorsener for image processing tasks, particularly web applications and content management systems that accept user-uploaded images. Attackers can exploit this flaw by uploading a maliciously crafted gif file to any system that uses the vulnerable library, resulting in immediate denial of service for the affected application. The impact extends beyond simple service interruption as the crash can potentially be leveraged in larger attack chains, especially when combined with other vulnerabilities or used as a component in distributed denial of service attacks. The vulnerability affects any system running ImageWorsener 1.3.0 or earlier versions, making it particularly dangerous in environments where multiple applications depend on this library for image handling capabilities.
The mitigation strategy for CVE-2017-7962 primarily involves immediate upgrading to a patched version of ImageWorsener that addresses the divide-by-zero condition through proper input validation and error handling mechanisms. System administrators should implement comprehensive patch management procedures to ensure all instances of the vulnerable library are updated across the organization. Additionally, implementing input validation at multiple layers including file type checking, size limitations, and content analysis can provide defense-in-depth measures against similar vulnerabilities. Organizations should also consider implementing proper error handling and graceful degradation mechanisms in their applications to prevent single points of failure when encountering malformed input data. The vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a clear example of how image processing libraries can become attack vectors when proper input sanitization is not implemented.