CVE-2016-3190 in Cairo
Summary
by MITRE
The fill_xrgb32_lerp_opaque_spans function in cairo-image-compositor.c in cairo before 1.14.2 allows remote attackers to cause a denial of service (out-of-bounds read and application crash) via a negative span length.
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Analysis
by VulDB Data Team • 10/08/2024
The vulnerability identified as CVE-2016-3190 resides within the cairo graphics library, specifically in the fill_xrgb32_lerp_opaque_spans function located in cairo-image-compositor.c. This issue affects cairo versions prior to 1.14.2 and represents a critical security flaw that can be exploited by remote attackers to execute denial of service attacks. The vulnerability manifests when the function processes graphical data with negative span lengths, creating conditions that lead to out-of-bounds memory reads and subsequent application crashes. This flaw falls under the category of input validation weaknesses and can be classified as a CWE-129 vulnerability, which specifically addresses insufficient checking of the length of input data. The attack vector is particularly concerning as it can be triggered remotely through crafted graphical content, making it a significant threat to applications that utilize cairo for rendering operations.
The technical implementation of this vulnerability exploits the lack of proper bounds checking within the graphics composition functions of cairo. When negative span lengths are processed, the function fails to validate the input parameters before proceeding with memory access operations. This results in memory corruption patterns that cause the application to read data from memory locations outside the intended buffer boundaries. The out-of-bounds read operations can lead to unpredictable behavior including segmentation faults, application crashes, and potential information disclosure. The vulnerability is particularly dangerous in server environments where cairo is used for processing untrusted graphical content from web browsers or other external sources. The flaw demonstrates poor defensive programming practices and highlights the importance of input validation in graphics processing libraries that handle user-provided data.
From an operational perspective, this vulnerability can severely impact systems that rely on cairo for rendering graphical content, including web browsers, graphic design applications, and server-side rendering engines. The denial of service condition can be triggered by sending maliciously crafted image data or graphical elements to applications using vulnerable cairo versions. Attackers can exploit this weakness to disrupt services, cause application instability, and potentially create denial of service scenarios that affect end users. The impact extends beyond simple crashes as the vulnerability can be used to gain information about memory layout or application state, making it potentially useful for more advanced exploitation techniques. This vulnerability is particularly concerning for web applications that process user-uploaded images or graphics, as it can be leveraged to cause widespread service disruption across multiple users.
The recommended mitigation strategy involves upgrading to cairo version 1.14.2 or later, which includes patches addressing the input validation issues in the fill_xrgb32_lerp_opaque_spans function. System administrators should prioritize patching affected systems and verify that all applications using cairo have been updated to versions that contain the security fixes. Additionally, implementing proper input validation at application layers can provide defense-in-depth measures against similar vulnerabilities. Organizations should also consider implementing network segmentation and access controls to limit exposure to potential attackers. The vulnerability highlights the importance of regular security updates and proper code review processes that include thorough testing of boundary conditions in graphics processing libraries. Security monitoring should include detection of unusual application behavior or crash patterns that might indicate exploitation attempts. This vulnerability serves as a reminder of the critical need for maintaining up-to-date graphics libraries and implementing proper security controls in environments where graphical processing is a core functionality. The ATT&CK framework categorizes this vulnerability under privilege escalation and denial of service tactics, as it can be used to disrupt services and potentially gain unauthorized access to system resources through application instability.