CVE-2020-0799 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists in Microsoft Windows when the Windows kernel fails to properly handle parsing of certain symbolic links, aka 'Windows Kernel Elevation of Privilege Vulnerability'.
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Analysis
by VulDB Data Team • 04/10/2024
This vulnerability represents a critical elevation of privilege flaw within the Windows kernel that stems from improper handling of symbolic link parsing operations. The issue resides in how the kernel processes certain symbolic link structures, creating opportunities for malicious actors to escalate their privileges from standard user level to system level access. The vulnerability specifically affects the Windows kernel's symbolic link processing mechanisms, which are fundamental components used throughout the operating system for file system navigation and resource management. Attackers can exploit this weakness by crafting specially formatted symbolic links that cause the kernel to mishandle memory references or access control checks during the parsing process. The flaw enables unauthorized users to bypass normal security boundaries and gain elevated privileges without proper authentication or authorization.
The technical nature of this vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow conditions. The kernel's failure to properly validate symbolic link structures during parsing creates a pathway for memory corruption that can be leveraged for privilege escalation. From an operational perspective, this vulnerability represents a significant threat to Windows environments as it allows attackers to gain system-level access through seemingly benign file system operations. The attack surface includes any application or user process that interacts with symbolic links, particularly those involving file system traversal, directory operations, or system resource management. The vulnerability is particularly dangerous because it can be exploited through multiple vectors including file system operations, network file sharing, and even through legitimate administrative tools that process symbolic links.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data exfiltration capabilities. Once an attacker achieves system-level privileges through this vulnerability, they can modify critical system files, install persistent backdoors, monitor network traffic, and access sensitive user data. The exploitability of this vulnerability is enhanced by the fact that symbolic link processing occurs frequently throughout normal Windows operations, making detection difficult and exploitation relatively straightforward. Organizations running affected Windows versions face significant risk as this vulnerability can be exploited remotely or locally, depending on the specific attack scenario and target system configuration. The vulnerability's impact is further amplified by the fact that it affects core kernel components that are essential for system operation, meaning that exploitation could potentially lead to system instability or complete system compromise.
Mitigation strategies for this vulnerability should focus on immediate patch deployment through Microsoft's regular security updates, as the primary fix involves correcting the kernel's symbolic link parsing logic. Organizations should implement comprehensive monitoring for unusual file system operations, particularly those involving symbolic link creation or modification, as potential indicators of exploitation attempts. Network segmentation and access control measures can help limit the potential impact of successful exploitation by restricting lateral movement within compromised environments. System administrators should also consider implementing additional security controls such as application whitelisting, mandatory access controls, and regular security audits of file system operations. The vulnerability highlights the importance of kernel-level security hardening and proper input validation for system-critical components, aligning with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation'. Organizations should also maintain robust incident response procedures specifically designed to handle kernel-level exploitation attempts, as detection and remediation of such vulnerabilities requires specialized technical expertise and system recovery procedures.