CVE-2018-12600 in ImageMagick
Summary
by MITRE
In ImageMagick 7.0.8-3 Q16, ReadDIBImage and WriteDIBImage in coders/dib.c allow attackers to cause an out of bounds write via a crafted file.
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Analysis
by VulDB Data Team • 03/28/2023
The vulnerability identified as CVE-2018-12600 represents a critical out-of-bounds write flaw within ImageMagick's handling of Device Independent Bitmap (DIB) image files. This issue affects ImageMagick versions up to 7.0.8-3 and specifically impacts the ReadDIBImage and WriteDIBImage functions located in the coders/dib.c source file. The flaw arises when processing maliciously crafted DIB files that contain malformed header structures or dimension values, leading to improper memory allocation and subsequent buffer overflow conditions during image processing operations.
The technical exploitation of this vulnerability occurs through improper validation of DIB file headers and dimensions before memory allocation takes place. When ImageMagick attempts to read or write DIB image files, the application fails to adequately verify the legitimacy of the file structure, particularly the width, height, and color depth parameters within the DIB headers. This validation gap allows attackers to craft files with oversized or malformed dimensions that cause the application to allocate insufficient memory buffers, subsequently leading to memory corruption when the application attempts to write data beyond the allocated buffer boundaries. The out-of-bounds write vulnerability falls under CWE-787, which specifically addresses out-of-bounds write conditions in software applications.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it presents significant security risks to systems processing untrusted image files. Attackers can leverage this flaw to execute arbitrary code on vulnerable systems, potentially leading to complete system compromise. The vulnerability is particularly dangerous in web applications or services that accept image uploads, as it allows remote code execution through crafted image files without requiring authentication. The attack surface includes email servers, content management systems, image processing services, and any application that utilizes ImageMagick for image handling operations. This vulnerability aligns with ATT&CK technique T1203, which involves exploitation of software vulnerabilities for remote code execution, and demonstrates how file format parsing flaws can be weaponized for system compromise.
Mitigation strategies for CVE-2018-12600 involve immediate patching of ImageMagick installations to versions that address the buffer overflow conditions in the DIB file handling code. System administrators should implement file type validation and sanitization measures, particularly for image uploads in web applications, by verifying file headers and implementing strict content filtering. Network-level protections can include implementing file type restrictions at firewalls or web application firewalls to prevent DIB files from reaching vulnerable systems. Additionally, organizations should consider implementing sandboxed environments for image processing operations and establishing robust input validation procedures that check image dimensions and structure before processing. The vulnerability highlights the importance of proper memory management and input validation in image processing libraries, emphasizing the need for comprehensive security testing of file format parsers. Organizations should also consider implementing automated vulnerability scanning and monitoring systems to detect and respond to exploitation attempts targeting known vulnerabilities in image processing software components.