CVE-2016-0019 in Windows
Summary
by MITRE
The Remote Desktop Protocol (RDP) service implementation in Microsoft Windows 10 Gold and 1511 allows remote attackers to bypass intended access restrictions and establish sessions for blank-password accounts via a modified RDP client, aka "Windows Remote Desktop Protocol Security Bypass Vulnerability."
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Analysis
by VulDB Data Team • 07/03/2022
The vulnerability identified as CVE-2016-0019 represents a critical security flaw in Microsoft Windows 10 operating systems, specifically affecting the Remote Desktop Protocol implementation. This vulnerability allows remote attackers to circumvent authentication mechanisms and establish unauthorized sessions using blank-password accounts, fundamentally undermining the security posture of affected systems. The issue stems from improper validation of authentication credentials within the RDP service, creating a pathway for malicious actors to gain unauthorized access without proper credentials. The vulnerability is particularly concerning as it affects Windows 10 Gold and 1511 versions, which were widely deployed in enterprise environments and consumer markets during that period. This security bypass enables attackers to exploit the RDP service directly, potentially leading to full system compromise and lateral movement within networks.
The technical flaw manifests in the RDP service's handling of authentication requests, where the implementation fails to properly validate the presence of valid credentials when establishing sessions. Specifically, the vulnerability allows attackers to craft modified RDP client connections that can bypass the normal authentication flow, enabling session establishment even when no password is provided. This occurs because the RDP implementation does not adequately enforce credential requirements for account access, particularly when dealing with accounts that have blank or null passwords. The flaw exists in the protocol handling layer where the service accepts connections without proper verification of authentication tokens or credentials, creating an authentication bypass condition that violates standard security practices. According to CWE classification, this vulnerability maps to CWE-287, which addresses improper authentication issues in software implementations, and specifically relates to improper authorization due to weak credential validation mechanisms.
The operational impact of CVE-2016-0019 extends beyond simple unauthorized access, as it enables sophisticated attack scenarios that can lead to complete system compromise. Attackers can leverage this vulnerability to establish persistent access to targeted systems, potentially using the compromised RDP service as a foothold for further network infiltration. The ability to connect via blank-password accounts significantly expands the attack surface, as many systems may have accounts with weak or no passwords configured for administrative access. This vulnerability particularly affects enterprise environments where RDP services are commonly enabled for remote administration, making organizations vulnerable to automated scanning and exploitation attempts. The threat landscape for this vulnerability aligns with ATT&CK technique T1021.001, which covers remote services such as RDP, making it a prime target for lateral movement and privilege escalation activities. Organizations with exposed RDP endpoints face heightened risk of ransomware deployment, data exfiltration, and persistent threat actor presence.
Mitigation strategies for CVE-2016-0019 should prioritize immediate patch deployment through Microsoft's security updates, which address the core authentication bypass issue in the RDP implementation. System administrators must ensure that all Windows 10 systems are updated to the latest security patches, particularly those addressing the RDP service vulnerabilities. Network segmentation and access control measures should be implemented to restrict RDP access to authorized users only, including the deployment of network access control lists and firewall rules that limit RDP port exposure. Additional protective measures include disabling unused RDP functionality, implementing strong authentication requirements for all accounts, and monitoring for anomalous RDP connection patterns that may indicate exploitation attempts. Organizations should also consider implementing multi-factor authentication for RDP access, as well as regular security audits to identify and remediate accounts with blank or weak passwords. The vulnerability underscores the importance of proper credential management and access control policies, aligning with security frameworks that emphasize the principle of least privilege and comprehensive authentication mechanisms. Regular vulnerability assessments and penetration testing should be conducted to identify similar authentication bypass vulnerabilities in other network services and applications.