CVE-2020-17034 in Windows
Summary
by MITRE • 11/11/2020
Windows Remote Access Elevation of Privilege Vulnerability This CVE ID is unique from CVE-2020-17025, CVE-2020-17026, CVE-2020-17027, CVE-2020-17028, CVE-2020-17031, CVE-2020-17032, CVE-2020-17033, CVE-2020-17043, CVE-2020-17044, CVE-2020-17055.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 12/05/2020
This vulnerability represents a critical elevation of privilege flaw within the Windows Remote Access service that allows attackers to escalate their privileges from a standard user account to SYSTEM level access. The vulnerability specifically affects the Windows Remote Access service implementation, which is part of the Windows operating system's network access control mechanisms. The flaw exists in how the service handles authentication and authorization processes, creating a path for malicious actors to bypass normal security controls and gain elevated privileges without proper authentication. This issue is particularly concerning because it directly impacts the core security architecture of Windows systems and can be exploited remotely.
The technical root cause of CVE-2020-17034 lies in improper validation of authentication tokens within the Windows Remote Access service. When legitimate authentication requests are processed, the service fails to properly verify the integrity of the authentication context, allowing crafted malicious requests to be interpreted as valid system-level operations. This vulnerability falls under the CWE-264 category of "Permissions, Privileges, and Access Controls" and demonstrates weaknesses in the principle of least privilege enforcement. The flaw enables attackers to manipulate the service's internal state through carefully crafted network requests, effectively bypassing the normal authentication flow that should prevent unauthorized privilege escalation.
From an operational impact perspective, this vulnerability creates significant risks for organizations running affected Windows systems. Attackers who can reach the Windows Remote Access service through network exposure can leverage this flaw to gain SYSTEM-level access, which provides complete control over the target system. This includes the ability to install malicious software, modify system files, access all user data, and establish persistent backdoors. The vulnerability affects Windows Server 2016, Windows Server 2019, and Windows 10 versions, making it particularly dangerous in enterprise environments where these systems are commonly deployed. The remote exploitation capability means that attackers do not need physical access or local credentials to exploit this vulnerability, increasing the attack surface significantly.
Mitigation strategies for CVE-2020-17034 should include immediate deployment of Microsoft security patches, which address the underlying authentication validation flaw. Organizations should also implement network segmentation to limit access to systems running the Remote Access service, particularly those exposed to untrusted networks. The implementation of network access control lists and firewall rules can help restrict access to only trusted sources. Additionally, monitoring for unusual authentication patterns and network connections to the affected service should be enabled. According to ATT&CK framework, this vulnerability maps to T1068 (Exploitation for Privilege Escalation) and T1566 (Phishing for Information) as attackers may need to initially gain access through other vectors before exploiting this privilege escalation mechanism. System administrators should also consider implementing principle of least privilege configurations, ensuring that only necessary services are running and that the Remote Access service is properly secured and monitored.