CVE-2020-0771 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists when the Windows CSC Service improperly handles memory.To exploit this vulnerability, an attacker would first have to gain execution on the victim system, aka 'Windows CSC Service Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-0769.
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Analysis
by VulDB Data Team • 04/10/2024
The Windows CSC Service Elevation of Privilege Vulnerability represents a critical security flaw in Microsoft Windows operating systems that allows attackers to escalate their privileges from standard user level to system level. This vulnerability specifically affects the Client Server Runtime Subsystem (CSRSS) service which manages console sessions and process creation in Windows environments. The issue stems from improper memory handling within the CSC service, creating a potential pathway for malicious actors to execute arbitrary code with elevated privileges. The vulnerability is particularly concerning because it requires only initial execution access on the target system, making it a preferred attack vector for adversaries seeking to establish persistent system-level access. The flaw exists in the way the service processes memory allocations and deallocations, potentially allowing for memory corruption that can be exploited through crafted input or malicious code execution.
This vulnerability operates at the kernel level and specifically targets the CSRSS service which is responsible for managing console sessions and process creation. The memory handling flaw manifests when the CSC service processes certain memory operations without proper validation or bounds checking, creating opportunities for attackers to manipulate memory structures. The vulnerability can be triggered through various attack vectors including malicious file execution, network-based attacks, or social engineering techniques that lead to initial system compromise. According to CWE classification, this vulnerability maps to CWE-125: "Out-of-bounds Read" and CWE-787: "Out-of-bounds Write" which are common memory corruption vulnerabilities that can lead to privilege escalation. The attack chain typically begins with a low-privilege user gaining initial access through phishing, exploit kits, or other initial compromise methods, followed by exploitation of this memory handling flaw to achieve system-level privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete system control capabilities. Once exploited, attackers can install persistent backdoors, modify system files, access all user data, and establish covert communication channels. The vulnerability affects multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it a widespread concern across enterprise environments. Organizations running affected systems face significant risk of data breaches, system compromise, and potential lateral movement within networks. The vulnerability's exploitation can lead to complete system takeover and persistent access, making it a high-value target for both nation-state actors and cybercriminal organizations. From an ATT&CK framework perspective, this vulnerability maps to T1068: "Exploitation for Privilege Escalation" and T1059: "Command and Scripting Interpreter" which represents the techniques used to leverage the vulnerability for system control and persistence.
Mitigation strategies for this vulnerability require immediate patch deployment from Microsoft as the primary defense mechanism. Organizations should ensure all Windows systems receive the relevant security updates and patches released by Microsoft to address this memory handling flaw. Network segmentation and access controls should be implemented to limit potential attack vectors and reduce the impact of initial compromise. Security monitoring should focus on detecting anomalous process creation, memory access patterns, and unusual privilege escalation events within the system. Endpoint detection and response solutions should be configured to identify potential exploitation attempts through behavioral analysis. Regular security assessments and vulnerability scanning should be conducted to identify systems that may have been compromised or remain unpatched. Additionally, organizations should implement principle of least privilege controls and maintain comprehensive system monitoring to detect and respond to potential exploitation attempts. The vulnerability's classification as a critical issue by Microsoft emphasizes the urgency of implementing these mitigations across all affected systems.