CVE-2018-18016 in ImageMagick
Summary
by MITRE
ImageMagick 7.0.7-28 has a memory leak vulnerability in WritePCXImage in coders/pcx.c.
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Analysis
by VulDB Data Team • 05/23/2023
The vulnerability identified as CVE-2018-18016 represents a critical memory leak flaw within ImageMagick's PCX image format handling functionality. This issue specifically affects ImageMagick version 7.0.7-28 and resides within the WritePCXImage function located in the coders/pcx.c source file. The memory leak occurs when processing specially crafted PCX image files, potentially leading to resource exhaustion and system instability. This vulnerability demonstrates a classic memory management flaw that can be exploited in environments where ImageMagick processes untrusted image data from external sources.
The technical implementation of this vulnerability stems from improper memory allocation and deallocation practices within the PCX image writing code path. When ImageMagick attempts to write PCX format images, the WritePCXImage function fails to properly release allocated memory blocks under certain error conditions or specific input parameter combinations. This memory leak manifests as incremental memory consumption that grows with each processed image, eventually leading to system performance degradation or complete resource exhaustion. The flaw operates at the application level within the image processing pipeline, making it particularly dangerous in server environments where multiple image operations occur sequentially.
The operational impact of CVE-2018-18016 extends beyond simple resource consumption, as it can enable denial of service attacks against systems running vulnerable ImageMagick versions. Attackers can craft malicious PCX files that trigger the memory leak during image processing operations, potentially causing system crashes, application hangs, or complete service unavailability. This vulnerability particularly affects web applications, content management systems, and any platform that accepts user-uploaded images and processes them with ImageMagick. The memory leak can compound over time in high-traffic environments, making it a significant concern for system administrators and security professionals managing image processing infrastructure.
Mitigation strategies for CVE-2018-18016 should prioritize immediate software updates to patched versions of ImageMagick where the memory leak has been addressed. System administrators should implement proper input validation and sanitization measures to prevent processing of untrusted image files, particularly in web-facing applications. Network segmentation and access controls can limit the potential impact of exploitation attempts, while monitoring systems should track memory usage patterns for early detection of resource exhaustion symptoms. The vulnerability aligns with CWE-401, which categorizes memory leaks as a fundamental weakness in software design. From an adversarial perspective, this flaw could be leveraged as part of broader attack chains targeting web applications, potentially enabling privilege escalation or persistent access through resource exhaustion techniques that align with ATT&CK tactics related to resource exhaustion and denial of service. Organizations should also consider implementing automated patch management processes and regular security assessments to prevent similar vulnerabilities from being exploited in their environments.