CVE-2015-8895 in ImageMagick
Summary
by MITRE
Integer overflow in coders/icon.c in ImageMagick 6.9.1-3 and later allows remote attackers to cause a denial of service (application crash) via a crafted length value, which triggers a buffer overflow.
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Analysis
by VulDB Data Team • 09/08/2020
The vulnerability identified as CVE-2015-8895 represents a critical integer overflow flaw within ImageMagick's icon coder component, specifically in the coders/icon.c file. This issue affects versions 6.9.1-3 and later, making it a widespread concern for systems utilizing this popular image processing library. The vulnerability stems from inadequate input validation when processing image file headers, particularly focusing on length fields that control buffer allocation. When a maliciously crafted image file is processed, the application fails to properly handle integer overflow conditions, leading to improper memory allocation calculations that ultimately result in buffer overflows.
The technical execution of this vulnerability involves the manipulation of image file structures where attackers craft specific length values that, when processed by ImageMagick's icon coder, cause integer arithmetic to overflow beyond the maximum representable value. This overflow condition results in the allocation of insufficient buffer space, which then gets overwritten when the application attempts to read or process the malformed image data. The flaw operates at the intersection of memory safety and input validation, where the software assumes that length fields in image headers will always contain valid values within expected ranges, failing to account for the possibility of integer overflow during arithmetic operations.
From an operational impact perspective, this vulnerability enables remote attackers to execute denial of service attacks against systems running vulnerable versions of ImageMagick. The application crash occurs during image processing operations, effectively preventing legitimate users from accessing or processing image files through affected systems. This makes the vulnerability particularly dangerous in web applications, content management systems, or any environment where user-uploaded images are processed automatically. The vulnerability can be exploited through various attack vectors including web uploads, email attachments, or any scenario where ImageMagick processes untrusted image data, potentially leading to widespread service disruption across affected platforms.
The vulnerability maps directly to CWE-190, which specifically addresses integer overflow conditions, and aligns with ATT&CK technique T1203, representing the use of malicious files to cause system instability. Organizations utilizing ImageMagick for image processing must consider the broader implications of this vulnerability within their attack surface, particularly in environments where automated image processing occurs. The remediation strategy involves immediate patching of ImageMagick to versions that address the integer overflow in the icon.c file, combined with implementing input validation measures that sanitize image file headers before processing. Additionally, network segmentation and application-level restrictions on image processing capabilities can provide additional defense-in-depth measures to mitigate the risk of exploitation.
This vulnerability demonstrates the critical importance of proper integer overflow handling in image processing libraries, where the combination of malformed input data and insufficient bounds checking creates opportunities for denial of service attacks. The flaw underscores the necessity for comprehensive testing of edge cases in image format parsing, particularly focusing on header field validation and memory allocation calculations. Organizations should implement regular vulnerability assessments targeting image processing components and maintain up-to-date security patches to prevent exploitation of similar integer overflow conditions in other software libraries. The incident serves as a reminder that seemingly benign image file processing operations can become attack vectors when proper input validation and memory safety measures are not implemented.