CVE-2018-20185 in GraphicsMagick
Summary
by MITRE
In GraphicsMagick 1.4 snapshot-20181209 Q8 on 32-bit platforms, there is a heap-based buffer over-read in the ReadBMPImage function of bmp.c, which allows attackers to cause a denial of service via a crafted bmp image file. This only affects GraphicsMagick installations with customized BMP limits.
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Analysis
by VulDB Data Team • 06/19/2023
The vulnerability identified as CVE-2018-20185 represents a critical heap-based buffer over-read flaw within GraphicsMagick version 1.4 snapshot-20181209 running on 32-bit platforms. This security issue resides within the ReadBMPImage function located in the bmp.c source file, specifically manifesting when processing maliciously crafted bmp image files. The vulnerability's exploitation potential is particularly concerning as it can lead to denial of service conditions that compromise system availability and stability. The flaw specifically targets installations that have implemented customized BMP limits, indicating that the vulnerability may not affect all deployments uniformly but rather those with particular configuration parameters.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions that occur when software attempts to access memory locations beyond the bounds of allocated buffers. This particular implementation flaw involves the BMP image parsing mechanism where insufficient validation occurs during the reading of bitmap image headers and data structures. The 32-bit platform constraint is significant as it limits the memory addressing capabilities and may amplify the impact of the buffer over-read condition. When an attacker submits a specially crafted bmp file, the ReadBMPImage function fails to properly validate the image dimensions and data structure parameters, leading to memory access violations that can cause application crashes or system instability.
From an operational perspective, this vulnerability presents substantial risks to systems that rely on GraphicsMagick for image processing tasks, particularly those handling untrusted image inputs from users or external sources. The denial of service impact can disrupt legitimate service operations and potentially provide attackers with a means to degrade system performance or availability. The vulnerability's requirement for customized BMP limits suggests that organizations with default installations may be less susceptible, but those with modified configuration parameters face elevated risk. This characteristic also indicates that the vulnerability may have been introduced through specific configuration changes rather than being inherent to the core software functionality.
The attack surface for this vulnerability extends to any application or service that utilizes GraphicsMagick's BMP image processing capabilities and accepts user-provided image files without proper validation. Systems in web applications, image processing pipelines, or content management systems that process bmp files are particularly at risk. The exploitation process requires minimal technical expertise and can be automated, making it attractive to threat actors seeking to disrupt services. Organizations should consider this vulnerability in the context of the ATT&CK framework, specifically under the reconnaissance and resource consumption categories where attackers may attempt to identify and exploit software weaknesses to achieve system compromise or availability disruption.
Mitigation strategies should prioritize immediate patching of GraphicsMagick installations to the latest stable versions that address this buffer over-read condition. System administrators should also implement input validation measures to filter or reject suspicious bmp files before they reach the GraphicsMagick processing layer. Network segmentation and access controls can help limit the potential impact of successful exploitation attempts. Additionally, monitoring systems should be configured to detect unusual application behavior or crash patterns that may indicate exploitation attempts. Organizations should conduct thorough vulnerability assessments to identify all systems running affected GraphicsMagick versions and ensure proper configuration management to prevent unauthorized customization that could expose systems to this vulnerability. The remediation process should also include updating any custom BMP limit configurations to align with secure default settings while maintaining necessary functionality for legitimate use cases.