CVE-2018-5685 in GraphicsMagick
Summary
by MITRE
In GraphicsMagick 1.3.27, there is an infinite loop and application hang in the ReadBMPImage function (coders/bmp.c). Remote attackers could leverage this vulnerability to cause a denial of service via an image file with a crafted bit-field mask value.
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Analysis
by VulDB Data Team • 01/20/2023
The vulnerability identified as CVE-2018-5685 represents a critical denial of service flaw within GraphicsMagick version 1.3.27, specifically affecting the ReadBMPImage function located in the coders/bmp.c source file. This issue manifests as an infinite loop condition that causes application hang, fundamentally compromising the system's availability and operational integrity. The vulnerability arises from insufficient input validation within the bitmap image processing pipeline, where crafted bit-field mask values in BMP image files can trigger malformed processing logic that never terminates.
The technical implementation of this vulnerability stems from improper boundary checking and loop termination conditions within the bitmap decoding routine. When GraphicsMagick processes a maliciously crafted BMP file containing a specially constructed bit-field mask, the parsing logic enters an infinite loop where control structures fail to progress toward a termination condition. This occurs because the application does not properly validate the bit-field mask values against expected ranges or logical constraints, allowing attacker-controlled input to manipulate loop counters or conditional branches in ways that prevent normal execution flow. The flaw aligns with CWE-835, which specifically addresses infinite loops or iterations without proper exit conditions, making it a classic example of insufficient loop termination logic.
From an operational perspective, this vulnerability presents a significant risk to systems relying on GraphicsMagick for image processing, particularly those handling untrusted user uploads or remote image sources. Remote attackers can exploit this flaw by simply providing a crafted BMP image file, requiring no authentication or privileged access, making it highly dangerous in web applications, content management systems, or any environment where image file processing occurs. The resulting application hang consumes system resources and can lead to complete service disruption, effectively implementing a denial of service attack that impacts availability and can potentially be amplified through multiple concurrent connections or batch processing scenarios.
The impact extends beyond simple service disruption to encompass broader system stability concerns, as the infinite loop can cause memory exhaustion, thread blocking, or process starvation in multi-threaded environments. Network-based applications processing images from untrusted sources become particularly vulnerable, as the attack can be executed remotely without requiring any special privileges or complex exploitation techniques. This vulnerability demonstrates a critical gap in input sanitization practices and highlights the importance of robust validation mechanisms in multimedia processing libraries. Security practitioners should consider implementing proper input validation, timeout mechanisms, and resource limiting controls to mitigate the risk of such denial of service conditions.
Mitigation strategies should include immediate patching of GraphicsMagick to version 1.3.28 or later, which contains the necessary fixes for the infinite loop condition. Organizations should also implement defensive measures such as input validation layers, timeout configurations, and resource monitoring to detect and prevent exploitation attempts. Additionally, the implementation of sandboxed processing environments and strict file format validation can provide additional protection against similar vulnerabilities in other image processing components. The vulnerability serves as a reminder of the critical importance of proper input validation and loop termination logic in security-critical applications, particularly those handling multimedia content where malformed input can lead to system instability and availability compromise. This issue is categorized under the ATT&CK technique T1499.004 for Unnecessary Administrative Access and T1566.001 for Phishing, as it enables attackers to perform availability attacks through crafted file delivery mechanisms.