CVE-2017-13768 in ImageMagick
Summary
by MITRE
Null Pointer Dereference in the IdentifyImage function in MagickCore/identify.c in ImageMagick through 7.0.6-10 allows an attacker to perform denial of service by sending a crafted image file.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2017-13768 represents a critical null pointer dereference flaw within the ImageMagick image processing library, specifically within the IdentifyImage function located in MagickCore/identify.c. This issue affects versions of ImageMagick through 7.0.6-10 and demonstrates a fundamental programming error that can be exploited to cause denial of service conditions. The vulnerability arises from insufficient input validation and error handling within the image identification process, where the software fails to properly check for null pointers before dereferencing them during image format detection and analysis operations.
The technical implementation of this vulnerability occurs when ImageMagick processes specially crafted image files that trigger the IdentifyImage function to attempt dereferencing a null pointer. This typically happens when the software encounters malformed image data that does not conform to expected format specifications, causing the internal pointer validation mechanisms to fail. The flaw manifests as a segmentation fault or access violation when the application attempts to access memory at a null address, resulting in process termination. This behavior aligns with CWE-476, which specifically addresses null pointer dereference vulnerabilities, and demonstrates how improper memory management can lead to system instability and service disruption.
From an operational perspective, this vulnerability presents a significant risk to systems that utilize ImageMagick for image processing, particularly those that accept user-uploaded content or process images from untrusted sources. Attackers can exploit this weakness by crafting malicious image files that, when processed by vulnerable ImageMagick installations, will cause the application to crash and terminate unexpectedly. This denial of service condition can be particularly damaging in web applications, content management systems, or any service that relies on image processing capabilities, as it can render the entire service unavailable to legitimate users. The impact extends beyond simple service interruption, as repeated exploitation can lead to resource exhaustion and system instability, making this a critical concern for enterprise environments and cloud-based services.
The mitigation strategies for CVE-2017-13768 involve immediate patching of affected ImageMagick installations to versions that contain the necessary code fixes and input validation improvements. Organizations should also implement proper input sanitization measures, including image format validation, size restrictions, and content filtering before processing user-uploaded images. Network-level protections such as intrusion detection systems can help identify exploitation attempts, while application-level defenses should include proper error handling, memory safety checks, and sandboxing techniques to prevent exploitation. Additionally, following the principle of least privilege and implementing proper resource limits can help minimize the impact of successful exploitation attempts. This vulnerability highlights the importance of robust input validation and proper error handling in security-critical software components, as outlined in the ATT&CK framework's defense evasion and execution tactics, where improper error handling can be leveraged to disrupt system operations and achieve denial of service conditions.