CVE-2017-1000044 in gtk-vnc
Summary
by MITRE
gtk-vnc 0.4.2 and older doesn't check framebuffer boundaries correctly when updating framebuffer which may lead to memory corruption when rendering
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/26/2019
The vulnerability identified as CVE-2017-1000044 affects gtk-vnc versions 0.4.2 and earlier, representing a critical memory corruption flaw within the Virtual Network Computing implementation. This issue resides in the framebuffer update mechanism where the software fails to properly validate framebuffer boundaries during rendering operations. The vulnerability stems from inadequate input validation and boundary checking within the graphics rendering pipeline, creating opportunities for attackers to manipulate memory structures through crafted framebuffer updates.
The technical flaw manifests when the gtk-vnc library processes framebuffer updates without sufficient validation of buffer limits and memory boundaries. This allows for potential buffer overflows or memory corruption scenarios when rendering graphics data, particularly in virtualized environments where VNC connections are established. The vulnerability specifically impacts the memory management routines responsible for handling framebuffer operations, where the lack of proper boundary checks enables attackers to write beyond allocated memory regions. This type of flaw aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, addressing heap-based buffer overflow scenarios that can occur when insufficient boundary checks are implemented.
The operational impact of this vulnerability extends significantly within virtualization and remote desktop environments where gtk-vnc is utilized for VNC client implementations. Attackers could potentially exploit this memory corruption to execute arbitrary code, escalate privileges, or cause denial of service conditions within systems that rely on gtk-vnc for graphical remote access. The vulnerability is particularly concerning in enterprise environments where VNC connections are commonly used for remote system administration, as it could enable unauthorized access to sensitive systems. Additionally, the flaw may affect various virtualization platforms and desktop environments that depend on gtk-vnc for remote desktop functionality, creating widespread potential impact across different system architectures and deployment scenarios.
Mitigation strategies for CVE-2017-1000044 primarily involve immediate upgrading to gtk-vnc version 0.4.3 or later, which includes proper boundary checking mechanisms and memory validation routines. System administrators should conduct comprehensive inventory assessments to identify all systems utilizing affected gtk-vnc versions and implement patch management procedures to address the vulnerability. Network segmentation and access controls should be enforced to limit exposure of systems running VNC services, while monitoring solutions should be deployed to detect anomalous behavior indicative of exploitation attempts. The vulnerability demonstrates the importance of input validation and boundary checking in graphics rendering libraries, aligning with ATT&CK technique T1059 for execution through command and scripting interpreters, and T1068 for privilege escalation through memory corruption exploitation. Organizations should also consider implementing runtime protection mechanisms and code analysis tools to identify similar boundary checking deficiencies in other software components that may be susceptible to analogous vulnerabilities.