CVE-2018-12293 in WebkitGTK+
Summary
by MITRE
The getImageData function in the ImageBufferCairo class in WebCore/platform/graphics/cairo/ImageBufferCairo.cpp in WebKit, as used in WebKitGTK+ prior to version 2.20.3 and WPE WebKit prior to version 2.20.1, is vulnerable to a heap-based buffer overflow triggered by an integer overflow, which could be abused by crafted HTML content.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability identified as CVE-2018-12293 represents a critical heap-based buffer overflow in the WebKit rendering engine's ImageBufferCairo implementation. This flaw exists within the getImageData function of the ImageBufferCairo class located in WebCore/platform/graphics/cairo/ImageBufferCairo.cpp. The vulnerability specifically affects WebKitGTK+ versions prior to 2.20.3 and WPE WebKit versions prior to 2.20.1, making these software versions susceptible to exploitation through malicious web content. The root cause of this vulnerability stems from an integer overflow condition that occurs during the processing of image data operations, creating a scenario where insufficient bounds checking allows memory allocation to exceed intended limits.
The technical exploitation of this vulnerability occurs when crafted HTML content triggers the getImageData function with malicious parameters that cause integer overflow conditions. When the system attempts to allocate memory for image data processing, the integer overflow results in a smaller allocated buffer than required, leading to heap corruption when the application attempts to write beyond the allocated memory boundaries. This type of vulnerability falls under CWE-190, which specifically addresses integer overflow conditions that can result in buffer overflows, and aligns with ATT&CK technique T1203, where adversaries leverage memory corruption vulnerabilities to execute arbitrary code. The vulnerability is particularly dangerous because it can be triggered through standard web browsing activities without requiring user interaction beyond visiting malicious websites.
The operational impact of this vulnerability extends beyond simple memory corruption, as it creates opportunities for remote code execution and system compromise. Attackers can craft HTML pages containing malicious image data parameters that, when processed by vulnerable WebKit implementations, trigger the buffer overflow condition. This exploitation pathway allows adversaries to potentially execute arbitrary code with the privileges of the affected application, typically resulting in complete system compromise. The vulnerability's presence in widely used web browsing frameworks means that successful exploitation could affect numerous end-user systems, web applications, and enterprise environments that rely on these WebKit-based browsers. The heap-based nature of the overflow also complicates exploitation attempts as it may not always result in immediate crashes, instead allowing for more sophisticated attack vectors that can persist and remain undetected.
Mitigation strategies for CVE-2018-12293 primarily focus on immediate software updates and patches to the affected WebKit versions. Organizations should prioritize upgrading to WebKitGTK+ 2.20.3 or later and WPE WebKit 2.20.1 or later to eliminate the vulnerability. Additionally, implementing network-based security controls such as web application firewalls and content filtering solutions can provide additional protection layers. Browser hardening measures including sandboxing, memory protection mechanisms, and strict content security policies should be enabled to reduce the potential impact of successful exploitation attempts. Regular security assessments and vulnerability scanning of web applications and browser environments help identify systems that may still be running vulnerable versions, ensuring comprehensive protection across the organization's attack surface.