CVE-2020-0757 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists when Windows improperly handles Secure Socket Shell remote commands, aka 'Windows SSH Elevation of Privilege Vulnerability'.
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Analysis
by VulDB Data Team • 02/12/2020
The vulnerability identified as CVE-2020-0757 represents a critical elevation of privilege flaw within the Windows Secure Shell (SSH) implementation that allows attackers to escalate their privileges from a standard user account to SYSTEM level access. This vulnerability specifically affects how Windows handles remote SSH commands, creating a pathway for malicious actors to bypass normal security controls and gain unauthorized administrative access to affected systems. The issue stems from improper validation and handling of remote commands executed through the SSH protocol, which is commonly used for secure remote administration and system management tasks.
From a technical perspective, the vulnerability manifests when Windows SSH server processes remote commands submitted by authenticated users. The flaw occurs in the command execution pipeline where input validation is insufficient, allowing specially crafted commands to be interpreted and executed with elevated privileges. This misconfiguration enables attackers to manipulate the command processing logic and potentially execute arbitrary code with the highest system privileges. The vulnerability is particularly concerning because it operates at the protocol level within the Windows SSH implementation, making it difficult to detect through traditional network monitoring approaches. According to CWE classification, this vulnerability maps to CWE-20: Improper Input Validation, as the system fails to properly validate and sanitize input received through SSH remote commands, and potentially CWE-78: Improper Neutralization of Special Elements used in OS Commands, which relates to the execution of operating system commands with insufficient sanitization.
The operational impact of CVE-2020-0757 is severe and far-reaching across enterprise environments that utilize Windows SSH services for remote administration. Attackers exploiting this vulnerability can gain complete control over affected systems, potentially leading to data exfiltration, lateral movement within networks, and establishment of persistent backdoors. The vulnerability affects multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, creating widespread exposure across enterprise infrastructures. Organizations using SSH for remote administration, system maintenance, and automated deployment processes face significant risk as this vulnerability can be exploited remotely without requiring additional authentication credentials beyond initial SSH access. The attack vector is particularly dangerous because it leverages legitimate administrative protocols, making detection challenging for security monitoring systems that may not flag normal SSH traffic as malicious.
Mitigation strategies for CVE-2020-0757 should prioritize immediate patch deployment through Microsoft's security updates, as the vendor has released comprehensive fixes addressing the privilege escalation flaw in affected Windows versions. Organizations should implement network segmentation and access control measures to limit SSH access to only necessary administrative personnel and systems. Security administrators should consider disabling SSH services on systems where they are not required for legitimate business operations, particularly on endpoints and workstations that do not require remote administration capabilities. Additional protective measures include implementing strict SSH command restrictions, monitoring for unusual command execution patterns, and deploying intrusion detection systems capable of identifying anomalous SSH behavior. The ATT&CK framework categorizes this vulnerability under T1068: Exploitation for Privilege Escalation, highlighting the need for comprehensive endpoint protection and privilege management controls. Organizations should also conduct thorough vulnerability assessments to identify all systems running SSH services and ensure proper patch management processes are in place to prevent similar vulnerabilities from remaining unaddressed in the future.