CVE-2020-0844 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists when Connected User Experiences and Telemetry Service improperly handles file operations, aka 'Connected User Experiences and Telemetry Service Elevation of Privilege Vulnerability'.
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Analysis
by VulDB Data Team • 04/10/2024
The CVE-2020-0844 vulnerability represents a critical elevation of privilege flaw within Microsoft's Connected User Experiences and Telemetry Service, which operates under the Windows operating system. This service is responsible for collecting telemetry data and managing user experience related information for Microsoft products, making it a prime target for malicious exploitation. The vulnerability stems from improper handling of file operations within the service, creating a pathway for unauthorized privilege escalation that could allow attackers to execute arbitrary code with elevated system privileges. The flaw specifically affects Windows 10 versions 1903 and 1909, as well as Windows Server 2019 and Windows Server 2016, where the service's inadequate validation of file operations creates a security gap that can be exploited by local attackers with standard user privileges.
The technical implementation of this vulnerability involves the Connected User Experiences and Telemetry Service running with elevated privileges while processing file operations that do not properly validate or sanitize input paths. Attackers can exploit this by manipulating file system operations to gain access to restricted resources or execute code with SYSTEM level privileges. The service's failure to properly validate file paths and operations creates a condition where malicious files can be placed in specific locations and then executed with elevated permissions. This type of vulnerability falls under the CWE-22 category of Improper Limitation of a Pathname to a Restricted Directory, commonly known as Path Traversal, which is a well-documented weakness in software security. The vulnerability represents a classic case of insufficient input validation combined with elevated service privileges, creating a dangerous combination that allows privilege escalation without requiring initial administrative access.
The operational impact of CVE-2020-0844 extends beyond simple privilege escalation, as it provides attackers with a persistent foothold within Windows environments. Once exploited, the vulnerability allows attackers to execute code with SYSTEM privileges, potentially enabling full system compromise, data exfiltration, and lateral movement within network environments. The vulnerability's location within the telemetry service means it operates continuously in the background, providing attackers with a stable attack surface that does not require user interaction to maintain access. This characteristic aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, where attackers can leverage the elevated privileges to execute malicious commands or establish persistence mechanisms. The vulnerability is particularly concerning in enterprise environments where telemetry services are often enabled by default and run with elevated privileges, making the attack surface larger and more accessible to threat actors.
Mitigation strategies for CVE-2020-0844 should focus on immediate patching of affected Windows versions, as Microsoft released security updates in the May 2020 Patch Tuesday releases. Organizations should also implement additional security controls including disabling unnecessary telemetry services where possible, monitoring for suspicious file operations in the affected service directories, and applying principle of least privilege configurations to limit the service's access to system resources. Network segmentation and monitoring solutions should be deployed to detect anomalous behavior from the telemetry service that could indicate exploitation attempts. The vulnerability demonstrates the importance of proper privilege separation and input validation in system services, with the ATT&CK framework highlighting similar patterns in privilege escalation techniques that involve service manipulation and file system exploitation. Security teams should also consider implementing application whitelisting policies to prevent unauthorized execution of binaries that could exploit similar vulnerabilities in other services, as the underlying principles of this vulnerability extend beyond just the specific service affected.