CVE-2017-12692 in ImageMagick
Summary
by MITRE
The ReadVIFFImage function in coders/viff.c in ImageMagick 7.0.6-6 allows remote attackers to cause a denial of service (memory consumption) via a crafted VIFF file.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2017-12692 represents a critical denial of service flaw within ImageMagick's VIFF image format processing capabilities. This issue specifically targets the ReadVIFFImage function located in the coders/viff.c source file, which is responsible for handling the Visualization Image Format File specification. The vulnerability manifests when ImageMagick processes a specially crafted VIFF file, leading to excessive memory consumption that can ultimately result in system resource exhaustion and service unavailability. The flaw affects ImageMagick version 7.0.6-6, making it particularly concerning given the widespread adoption of this image processing library across various web applications and systems.
The technical nature of this vulnerability stems from inadequate input validation and memory management within the VIFF file parser. When a maliciously constructed VIFF file is processed, the ReadVIFFImage function fails to properly constrain memory allocation requests, allowing attackers to craft files that trigger exponential memory growth during parsing operations. This memory consumption pattern typically occurs through recursive or iterative processing of malformed data structures within the VIFF format, where the parser's handling of certain header fields or data segments causes it to allocate increasingly large memory blocks without proper bounds checking. The vulnerability operates at the application layer, making it accessible to remote attackers who can submit malicious files through web interfaces or file upload mechanisms that utilize ImageMagick for image processing.
From an operational perspective, this vulnerability poses significant risks to systems that rely on ImageMagick for image handling, particularly web applications that accept user-uploaded images. Attackers can exploit this flaw by uploading or submitting crafted VIFF files that, when processed by ImageMagick, consume excessive system resources and potentially cause system crashes or application hangs. The impact extends beyond simple service disruption, as the memory exhaustion can affect entire server processes or even cause system instability. This vulnerability is particularly dangerous in cloud environments or shared hosting scenarios where resource exhaustion on one service can impact other applications running on the same infrastructure, making it a prime target for resource exhaustion attacks that can be executed with minimal technical expertise.
The vulnerability aligns with CWE-400, which addresses "Uncontrolled Resource Consumption" and specifically relates to denial of service conditions caused by improper resource management. From an attack framework perspective, this issue can be categorized under ATT&CK technique T1499.004, which covers "Evasion: File System Evasion" and potentially T1566.002 for "Phishing with Social Engineering" when attackers craft malicious files to exploit this vulnerability through web-based attacks. Organizations using ImageMagick in their image processing workflows should prioritize immediate remediation, as the vulnerability can be exploited remotely without authentication requirements, making it particularly dangerous in public-facing applications. The fix typically involves updating to a patched version of ImageMagick where proper input validation and memory allocation limits have been implemented to prevent the excessive consumption patterns that trigger this vulnerability.
Mitigation strategies should include immediate patching of affected ImageMagick installations to version 7.0.6-7 or later, where the vulnerability has been addressed through improved input validation and memory management within the VIFF parser. Additionally, implementing file type validation and content inspection mechanisms can provide additional defense layers, ensuring that only properly formatted and verified image files are processed through ImageMagick. Network-level protections such as rate limiting and file size restrictions can also help reduce the impact of exploitation attempts. Organizations should also consider implementing sandboxing or containerization techniques for image processing operations to limit the potential damage from successful exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify any other potential weaknesses in image processing pipelines that might be susceptible to similar resource exhaustion attacks, particularly given the complex nature of image format parsing and the numerous potential attack vectors that exist within multimedia processing libraries.