CVE-2017-17682 in ImageMagick
Summary
by MITRE
In ImageMagick 7.0.7-12 Q16, a large loop vulnerability was found in the function ExtractPostscript in coders/wpg.c, which allows attackers to cause a denial of service (CPU exhaustion) via a crafted wpg image file that triggers a ReadWPGImage call.
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Analysis
by VulDB Data Team • 01/18/2023
The vulnerability identified as CVE-2017-17682 represents a critical denial of service flaw within ImageMagick's processing pipeline for wpg image files. This issue manifests in the ExtractPostscript function located within the coders/wpg.c source file, where a problematic loop structure creates an opportunity for attackers to exhaust system CPU resources through carefully crafted malicious wpg image files. The vulnerability specifically affects ImageMagick versions up to 7.0.7-12 Q16, making it a significant concern for systems that process untrusted image content. The flaw operates by triggering a ReadWPGImage call that executes an excessive loop, consuming disproportionate computational resources and potentially leading to system instability or complete service unavailability.
The technical nature of this vulnerability falls under CWE-835, which specifically addresses the issue of infinite loops or excessive iteration in software applications. This classification indicates that the flaw stems from inadequate loop termination conditions or improper input validation within the image processing code. When an attacker provides a malformed wpg file containing malicious loop parameters, the ExtractPostscript function enters an uncontrolled iterative process that consumes CPU cycles without proper bounds checking. The vulnerability demonstrates how image processing libraries can become attack vectors when they fail to implement adequate resource management and input sanitization measures. The loop structure in question likely contains recursive or iterative references that are not properly bounded by maximum iteration limits or input size constraints.
Operationally, this vulnerability presents a substantial risk to systems that utilize ImageMagick for image processing, particularly those handling user-uploaded content or processing images from untrusted sources. The denial of service impact can be severe as attackers can cause sustained CPU exhaustion, potentially leading to system resource starvation and service disruption. Systems that rely on automated image processing workflows, web applications accepting image uploads, or content management systems using ImageMagick for media handling are all vulnerable to exploitation. The attack requires minimal sophistication as it only necessitates crafting a specific wpg image file, making it particularly dangerous for automated exploitation. The vulnerability can be leveraged in distributed denial of service scenarios where multiple malicious files are processed simultaneously, amplifying the impact on target systems.
Mitigation strategies for CVE-2017-17682 primarily involve upgrading to ImageMagick version 7.0.7-13 or later, which contains the necessary patches to address the loop vulnerability. System administrators should implement comprehensive input validation and resource limiting measures when processing image files, including setting maximum file size limits and processing time constraints. The implementation of sandboxing techniques and restricted execution environments can help contain potential exploitation attempts. Organizations should also consider deploying automated monitoring systems that can detect unusual CPU utilization patterns indicative of denial of service attacks. Additionally, following the principle of least privilege and implementing proper access controls for image processing services can limit the potential impact of successful exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date software libraries and implementing robust security practices in image processing workflows as outlined in various cybersecurity frameworks and best practices.