CVE-2020-0834 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists when Windows improperly handles calls to Advanced Local Procedure Call (ALPC).An attacker who successfully exploited this vulnerability could run arbitrary code in the security context of the local system, aka 'Windows ALPC Elevation of Privilege Vulnerability'.
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Analysis
by VulDB Data Team • 04/10/2024
The vulnerability identified as CVE-2020-0834 represents a critical elevation of privilege flaw within the Windows operating system's handling of Advanced Local Procedure Call operations. This weakness resides in the kernel-mode components responsible for inter-process communication and system service management. The flaw specifically manifests when Windows processes ALPC calls without proper validation mechanisms, creating an opportunity for malicious actors to escalate their privileges from standard user level to full system access. The vulnerability impacts multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it particularly concerning for enterprise environments where these systems are prevalent.
The technical exploitation of this vulnerability leverages the improper validation of ALPC message handling within the Windows kernel. When an attacker crafts malicious ALPC calls, the system fails to adequately verify the legitimacy of these operations, allowing unauthorized code execution within the system context. This flaw falls under the Common Weakness Enumeration category CWE-119, which addresses weaknesses in memory handling and improper validation of input parameters. The vulnerability is particularly dangerous because it operates at the kernel level, where all system resources are accessible to the executing code. Attackers can exploit this by leveraging the ALPC interface to manipulate system calls and gain elevated privileges, effectively bypassing standard security boundaries that normally protect system integrity.
The operational impact of CVE-2020-0834 extends beyond simple privilege escalation, as it provides attackers with complete system control capabilities. Once successfully exploited, the vulnerability enables adversaries to install persistent backdoors, modify system files, access sensitive data repositories, and potentially establish footholds for further lateral movement within network environments. The attack surface is particularly broad since ALPC is a fundamental component used by numerous Windows system services and applications for communication between processes. According to the MITRE ATT&CK framework, this vulnerability maps to the privilege escalation technique T1068, specifically targeting the 'Local Privilege Escalation' tactic. The vulnerability also relates to T1547, which covers 'Registry Run Keys / Startup Folder' persistence mechanisms that attackers often establish after gaining elevated privileges.
Mitigation strategies for CVE-2020-0834 primarily focus on immediate patch application through Microsoft's regular security updates, as the vendor has released patches addressing the specific ALPC validation issues. System administrators should prioritize deployment of the relevant security updates across all affected Windows systems, particularly those with elevated privileges or network access. Network segmentation and principle of least privilege implementations can help limit the potential impact of successful exploitation by reducing the attack surface and limiting lateral movement capabilities. Additional protective measures include implementing application whitelisting policies, monitoring for anomalous ALPC activity, and conducting regular security assessments of system configurations. The vulnerability also underscores the importance of maintaining current security baselines and ensuring that all Windows systems receive timely security updates to prevent exploitation of known vulnerabilities. Organizations should also consider implementing behavioral analytics solutions that can detect unusual patterns in system call activity that might indicate exploitation attempts targeting this specific flaw.