CVE-2018-8960 in ImageMagick
Summary
by MITRE
The ReadTIFFImage function in coders/tiff.c in ImageMagick 7.0.7-26 Q16 does not properly restrict memory allocation, leading to a heap-based buffer over-read.
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Analysis
by VulDB Data Team • 02/24/2023
The vulnerability identified as CVE-2018-8960 resides within the ImageMagick image processing library, specifically in the ReadTIFFImage function located in coders/tiff.c. This flaw manifests in version 7.0.7-26 Q16 of the software, where the application fails to adequately validate memory allocation parameters when processing TIFF image files. The issue stems from insufficient input validation mechanisms that allow maliciously crafted TIFF files to trigger improper memory handling during image decoding operations. The vulnerability represents a critical security flaw that can be exploited by attackers to cause unexpected behavior in applications that utilize ImageMagick for image processing tasks.
The technical implementation of this vulnerability involves a heap-based buffer over-read condition that occurs when the ReadTIFFImage function processes malformed TIFF data structures. When ImageMagick attempts to parse TIFF headers and metadata, the function does not properly validate the size parameters specified in the image file's structure. This allows an attacker to craft a TIFF file with oversized dimension values or malformed data structures that cause the application to allocate insufficient memory buffers. The subsequent read operations attempt to access memory beyond the allocated buffer boundaries, potentially exposing sensitive data or causing application crashes. This type of vulnerability falls under the CWE-121 category of heap-based buffer overflow, though specifically manifests as an over-read condition rather than a traditional overflow.
The operational impact of CVE-2018-8960 extends beyond simple application instability, as it can be leveraged for more sophisticated attacks within the context of web applications and file processing services. When exploited, this vulnerability can lead to information disclosure through memory leaks, application crashes that result in denial of service conditions, or potentially more severe exploitation if combined with other vulnerabilities. The flaw is particularly dangerous in environments where ImageMagick is used to process untrusted user uploads, such as web applications, content management systems, or file conversion services. Attackers can craft malicious TIFF files that, when processed by vulnerable applications, trigger the buffer over-read condition and potentially expose system memory contents or cause arbitrary code execution depending on the exploitation context and memory layout.
Mitigation strategies for this vulnerability require immediate patching of affected ImageMagick installations to version 7.0.8-1 or later, which contains the necessary fixes for proper memory allocation validation. Organizations should also implement strict input validation for image file processing, particularly when handling user-uploaded content or untrusted sources. Network-based mitigations can include implementing file type filtering to prevent TIFF files from reaching vulnerable applications, or deploying web application firewalls that can detect and block malicious image file patterns. Additionally, system administrators should consider implementing sandboxing techniques for image processing operations and monitoring for unusual memory allocation patterns or application crashes that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper resource management in image processing libraries and aligns with ATT&CK technique T1203 for exploitation of memory corruption vulnerabilities in software components.