CVE-2017-12877 in ImageMagick
Summary
by MITRE
Use-after-free vulnerability in the DestroyImage function in image.c in ImageMagick before 7.0.6-6 allows remote attackers to cause a denial of service via a crafted file.
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Analysis
by VulDB Data Team • 12/16/2022
The vulnerability identified as CVE-2017-12877 represents a critical use-after-free flaw within ImageMagick's image processing library that exists in versions prior to 7.0.6-6. This vulnerability specifically affects the DestroyImage function in the image.c source file, creating a scenario where memory that has been freed is subsequently accessed by the application. The flaw manifests when ImageMagick processes maliciously crafted image files, allowing remote attackers to exploit this weakness without requiring any authentication or privileges. The security implications are severe as this vulnerability can be leveraged to cause a denial of service condition that effectively disrupts the normal operation of systems relying on ImageMagick for image processing tasks. The root cause stems from improper memory management practices where the application fails to properly validate or handle memory deallocation sequences during image destruction operations, leaving memory pointers in an invalid state.
The technical exploitation of this vulnerability occurs when a malicious file triggers the DestroyImage function to free memory resources that are then accessed again during subsequent processing operations. This creates a classic use-after-free condition where an attacker can manipulate the memory state to cause unpredictable behavior including application crashes, system instability, or potentially more severe consequences depending on the execution environment. The vulnerability is particularly dangerous because it can be triggered remotely through web applications or services that utilize ImageMagick for image handling, making it a significant threat vector for web-based attacks. The flaw operates at the memory management level, where the application's internal state becomes corrupted when it attempts to reference memory that has already been freed, leading to a cascade of failures that can result in complete service disruption.
From an operational perspective, this vulnerability poses substantial risk to organizations that rely on ImageMagick for image processing within their applications, web services, or content management systems. The impact extends beyond simple denial of service as the instability caused by memory corruption can potentially lead to more severe consequences including data loss, unauthorized access, or system compromise. The vulnerability is particularly concerning in web environments where users can upload or submit images that are then processed by ImageMagick, as this creates an automated attack surface that can be exploited at scale. Security practitioners must understand that this flaw can be weaponized through various attack vectors including email attachments, web uploads, or file sharing systems where image processing is automated. The vulnerability's remote exploitability makes it especially dangerous as attackers can target systems without requiring physical access or direct interaction with the target environment.
Organizations should implement immediate mitigations including upgrading to ImageMagick version 7.0.6-6 or later, which contains the necessary patches to address the memory management issues. Additional defensive measures include implementing strict input validation for all image files processed through ImageMagick, utilizing sandboxing techniques to isolate image processing operations, and deploying web application firewalls to detect and block suspicious file uploads. Security teams should also consider implementing automated monitoring for unusual application behavior that might indicate exploitation attempts, as well as maintaining detailed logs of image processing activities for forensic analysis. The vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software applications, and represents a typical attack pattern that would be categorized under the ATT&CK technique T1203 for legitimate program execution or T1059 for command and scripting interpreter usage. Organizations should also review their image processing pipelines to ensure proper error handling and memory management practices are in place to prevent similar vulnerabilities from emerging in their own codebases.