CVE-2019-13574 in MiniMagick
Summary
by MITRE
In lib/mini_magick/image.rb in MiniMagick before 4.9.4, a fetched remote image filename could cause remote command execution because Image.open input is directly passed to Kernel#open, which accepts a '|' character followed by a command.
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Analysis
by VulDB Data Team • 10/26/2023
The vulnerability identified as CVE-2019-13574 resides within the MiniMagick gem, a popular ruby library used for image processing that leverages ImageMagick's command-line tools. This flaw affects versions prior to 4.9.4 and represents a critical remote command execution vulnerability that stems from improper input validation when handling remote image URLs. The vulnerability specifically impacts the image.rb file within the lib directory where the Image.open method processes user-supplied URLs without adequate sanitization.
The technical root cause of this vulnerability lies in the direct pass-through of user-provided input to the Kernel#open method, which is designed to handle file operations and supports shell command execution through the pipe character '|'. When MiniMagick fetches a remote image, it accepts a URL that may contain malicious constructs where the pipe character followed by arbitrary commands can be interpreted by the underlying system shell. This occurs because the library does not properly validate or sanitize the remote filename before passing it to the system call, creating an injection vector that allows attackers to execute arbitrary commands on the system running the application.
The operational impact of this vulnerability is severe and far-reaching within applications that utilize MiniMagick for processing user-uploaded or externally sourced images. An attacker who can control the URL of a remote image can craft malicious URLs that execute commands with the privileges of the process running the application. This could lead to complete system compromise, data exfiltration, or further lateral movement within a network. The vulnerability is particularly dangerous in web applications where users can upload or provide image URLs, as it transforms a simple image processing feature into a potential attack vector for remote code execution. The risk is amplified when the application runs with elevated privileges or has access to sensitive system resources.
Mitigation strategies for CVE-2019-13574 focus primarily on upgrading to MiniMagick version 4.9.4 or later, which includes proper input validation and sanitization mechanisms. Organizations should also implement additional security measures such as validating and sanitizing all external URLs before processing them through MiniMagick, implementing network-level restrictions to prevent access to internal systems, and monitoring for suspicious command execution patterns. The vulnerability aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and maps to ATT&CK technique T1059.001 for command and scripting interpreter. Security teams should also consider implementing web application firewalls, input validation layers, and principle of least privilege access controls to reduce the potential impact of such vulnerabilities in their environments.