CVE-2017-13769 in ImageMagick
Summary
by MITRE
The WriteTHUMBNAILImage function in coders/thumbnail.c in ImageMagick through 7.0.6-10 allows an attacker to cause a denial of service (buffer over-read) by sending a crafted JPEG file.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2017-13769 represents a critical buffer over-read flaw within ImageMagick's thumbnail image processing functionality. This issue resides in the WriteTHUMBNAILImage function located in the coders/thumbnail.c file, affecting all versions up to and including 7.0.6-10. The vulnerability manifests when ImageMagick processes specially crafted JPEG files, creating a scenario where memory access occurs beyond the bounds of allocated buffer space. Such buffer over-read conditions can lead to unpredictable behavior and system instability, making this a significant concern for applications that rely on ImageMagick for image processing operations.
The technical exploitation of this vulnerability occurs through the manipulation of JPEG file structures that trigger improper memory handling during thumbnail generation. When a malicious JPEG file is processed by ImageMagick's thumbnail function, the software fails to properly validate buffer boundaries, allowing an attacker to craft input data that overflows allocated memory regions. This flaw falls under the Common Weakness Enumeration category CWE-125, which specifically addresses out-of-bounds read vulnerabilities. The vulnerability's impact extends beyond simple denial of service, as buffer over-reads can potentially lead to information disclosure or even arbitrary code execution depending on the system's memory layout and security mitigations in place.
From an operational perspective, this vulnerability poses substantial risks to web applications, content management systems, and any platform that accepts user-uploaded images for processing. Attackers can leverage this flaw to cause service disruption by consuming excessive system resources or triggering application crashes, effectively creating a denial of service condition. The vulnerability's exploitation requires minimal privileges and can be executed through simple file uploads, making it particularly dangerous in multi-user environments. Organizations using ImageMagick in production systems face significant exposure, as the flaw can be exploited by malicious users to disrupt services without requiring advanced technical skills or extensive system access.
The mitigation strategies for CVE-2017-13769 primarily focus on immediate version upgrades to patched releases of ImageMagick. Users should upgrade to version 7.0.6-11 or later, where the buffer over-read issue has been addressed through proper bounds checking and input validation. Additionally, implementing proper input sanitization at the application level can provide defense-in-depth protection, including validation of file types, size limitations, and sandboxed processing environments. Network-based mitigations such as web application firewalls can also help detect and block malicious file uploads. Organizations should also consider implementing principle of least privilege for image processing services, limiting the impact of potential exploitation through restricted system access and resource allocation controls. The vulnerability demonstrates the importance of proper memory management in image processing libraries and highlights the need for comprehensive security testing of third-party components in enterprise environments.