CVE-2017-16546 in ImageMagick
Summary
by MITRE
The ReadWPGImage function in coders/wpg.c in ImageMagick 7.0.7-9 does not properly validate the colormap index in a WPG palette, which allows remote attackers to cause a denial of service (use of uninitialized data or invalid memory allocation) or possibly have unspecified other impact via a malformed WPG file.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/06/2023
The vulnerability identified as CVE-2017-16546 resides within ImageMagick's handling of WPG (WordPerfect Graphics) image files through the ReadWPGImage function located in coders/wpg.c. This issue affects ImageMagick version 7.0.7-9 and represents a critical flaw in the software's input validation mechanisms. The vulnerability stems from insufficient validation of colormap indices within WPG palette structures, creating a scenario where malformed input can trigger unexpected behavior in the image processing pipeline.
The technical flaw manifests when ImageMagick attempts to parse WPG files that contain improperly structured colormap data. During the image reading process, the software does not adequately verify that colormap indices fall within valid bounds before attempting to access corresponding color data. This lack of proper validation allows attackers to craft malicious WPG files containing out-of-bounds index references that can cause the application to access uninitialized memory locations or attempt invalid memory allocations. The vulnerability operates at the intersection of buffer over-read conditions and improper input validation, both of which are categorized under CWE-125 and CWE-20 respectively in the Common Weakness Enumeration framework.
From an operational perspective, this vulnerability presents significant risks to systems that process untrusted image content, particularly those running ImageMagick as part of web applications, file processing services, or content management systems. Remote attackers can exploit this weakness to trigger denial of service conditions that may cause application crashes or resource exhaustion, effectively rendering the system unavailable to legitimate users. The potential for unspecified other impacts suggests that under certain conditions, this vulnerability could also enable more sophisticated attacks including privilege escalation or arbitrary code execution, though the exact attack vectors remain unspecified in the CVE description.
The impact extends beyond simple service disruption to encompass broader security implications for applications that rely on ImageMagick for image processing. Systems processing user-uploaded images, email attachments, or content from external sources become vulnerable to this attack vector, making it particularly dangerous in web environments where input validation is paramount. The vulnerability aligns with ATT&CK technique T1203 (Exploitation for Client Execution) and represents a classic example of how improper input validation can lead to remote code execution or denial of service conditions. Organizations utilizing ImageMagick should prioritize patching this vulnerability and implementing additional input validation layers to protect against similar classes of attacks.
Mitigation strategies should include immediate deployment of the patched ImageMagick version that addresses this specific validation issue, along with implementing comprehensive input sanitization measures for all image processing workflows. Network segmentation and application-level firewalls can help limit the attack surface, while regular security assessments should verify that no other similar validation flaws exist within the image processing pipeline. The vulnerability serves as a reminder of the critical importance of proper input validation in multimedia processing libraries and the potential consequences when such validation is insufficient.