CVE-2019-0694 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists due to an integer overflow in Windows Subsystem for Linux, aka 'Windows Subsystem for Linux Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2019-0682, CVE-2019-0689, CVE-2019-0692, CVE-2019-0693.
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Analysis
by VulDB Data Team • 08/01/2023
The vulnerability described in CVE-2019-0694 represents a critical elevation of privilege flaw within the Windows Subsystem for Linux (WSL) component of Microsoft Windows operating systems. This vulnerability specifically manifests as an integer overflow condition that occurs within the WSL subsystem implementation, allowing malicious actors to escalate their privileges from standard user level to administrative access. The flaw exists in the kernel-mode components responsible for managing Linux subsystem operations within the Windows environment, creating a pathway for unauthorized code execution with elevated privileges. The integer overflow condition typically arises when the system processes data that exceeds the maximum value that can be stored in a given integer variable, potentially leading to unexpected behavior and security breaches.
The technical exploitation of this vulnerability involves leveraging the integer overflow within WSL's memory management or process handling mechanisms to manipulate system resources and gain unauthorized access to privileged operations. Attackers can craft specific inputs or commands that trigger the overflow condition, causing the system to behave unpredictably and potentially allowing them to execute arbitrary code with elevated privileges. This flaw particularly affects systems running Windows 10 version 1803 and later versions, where the WSL functionality was introduced and subsequently enhanced. The vulnerability is particularly concerning because it operates at the kernel level, making it extremely difficult to detect and prevent through traditional user-mode security measures.
The operational impact of CVE-2019-0694 extends beyond simple privilege escalation, as successful exploitation can lead to complete system compromise and persistent access for attackers. Once an attacker gains elevated privileges through this vulnerability, they can modify system files, install malware, access sensitive data, and establish backdoors that persist across system reboots. The attack surface is particularly broad given that WSL is designed to provide Linux compatibility and command-line functionality within Windows, making it an attractive target for attackers seeking to exploit the underlying Windows kernel. The vulnerability also demonstrates the inherent security challenges associated with cross-platform subsystem implementations where Windows components interact with Linux-like environments, creating potential attack vectors that may not be immediately apparent through conventional security assessments.
Mitigation strategies for CVE-2019-0694 primarily involve applying Microsoft's security patches and updates that address the integer overflow condition within the WSL subsystem. System administrators should ensure that all Windows 10 systems are updated to the latest security patches, particularly those released in May 2019, which specifically addressed this vulnerability. Additionally, organizations should consider disabling WSL functionality on systems where it is not required, as this reduces the attack surface and eliminates the risk associated with this particular vulnerability. The implementation of network segmentation and access controls can further limit the potential impact of exploitation attempts, while continuous monitoring for unusual system behavior can help detect potential exploitation attempts. This vulnerability aligns with CWE-190, which describes integer overflow conditions, and represents a specific instance of how kernel-level flaws in subsystem implementations can create significant security risks.
The vulnerability also maps to several ATT&CK techniques including privilege escalation through kernel exploits and the use of legitimate system tools for malicious purposes. Attackers leveraging this vulnerability can employ techniques such as process injection and registry modification to maintain persistence within compromised systems. The security community has noted that this vulnerability highlights the importance of comprehensive security testing for cross-platform integration components, particularly those that operate at kernel level. Organizations should implement robust patch management procedures and consider the broader implications of enabling subsystems like WSL, as they can introduce complex security challenges that require careful monitoring and management. The incident underscores the critical need for security professionals to understand both the intended functionality and potential attack vectors of system components that provide compatibility layers between different operating environments.