CVE-2018-8441 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 affects Windows 10, Windows 10 Servers.
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Analysis
by VulDB Data Team • 08/16/2024
The vulnerability identified as CVE-2018-8441 represents a critical elevation of privilege flaw within the Windows Subsystem for Linux (WSL) component of Microsoft Windows operating systems. This vulnerability specifically targets the interaction between the Windows kernel and the Linux subsystem environment, creating a pathway for malicious actors to escalate their privileges from standard user level to administrator level. The issue affects all versions of Windows 10 and Windows 10 Server that have WSL enabled, making it a widespread concern across enterprise and consumer environments where Linux compatibility layers are utilized. The vulnerability stems from improper handling of integer values during memory allocation and buffer management processes within the subsystem's kernel components.
The technical root cause of this vulnerability lies in an integer overflow condition that occurs when processing certain data structures within the WSL implementation. This overflow manifests during the allocation of memory resources or when handling specific system calls that bridge the Windows kernel space with the Linux subsystem environment. When an integer value exceeds its maximum representable range, it wraps around to a smaller value, creating a situation where memory allocations become corrupted or improperly sized. This allows attackers to manipulate memory layout and potentially overwrite critical system structures or execute arbitrary code with elevated privileges. The vulnerability is categorized under CWE-190 as an Integer Overflow or Wraparound, which is a well-documented weakness that frequently leads to memory corruption and privilege escalation attacks.
The operational impact of CVE-2018-8441 extends beyond simple privilege escalation, as it fundamentally undermines the security boundaries between user processes and system-level operations within the Windows environment. Attackers who successfully exploit this vulnerability can gain complete control over affected systems, potentially leading to data exfiltration, system compromise, and lateral movement within network environments. The attack vector typically involves crafting specific inputs or system calls that trigger the integer overflow condition, which then allows for code execution in kernel mode. This type of vulnerability is particularly dangerous in enterprise environments where WSL is commonly enabled for development and testing purposes, as it provides a direct path to system compromise from any user account that has access to the subsystem. The vulnerability aligns with ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation" and T1059 which covers "Command and Scripting Interpreter" as attackers may leverage the compromised system to execute further malicious activities.
Mitigation strategies for CVE-2018-8441 primarily focus on immediate patch application from Microsoft, which addresses the integer overflow condition through proper input validation and bounds checking within the WSL subsystem components. Organizations should ensure that all affected Windows 10 and Windows 10 Server systems are updated with the relevant security patches released by Microsoft, as these updates contain fixes for the memory management routines that were vulnerable to integer overflow conditions. Additionally, administrators should consider disabling WSL on systems where it is not required, as this eliminates the attack surface entirely. Network segmentation and access controls should be implemented to limit exposure, particularly in environments where WSL is enabled. Monitoring should be enhanced to detect unusual system call patterns or memory allocation behaviors that might indicate exploitation attempts, and security teams should maintain awareness of related vulnerabilities in the WSL implementation that could compound the risk of successful attacks. The vulnerability demonstrates the importance of rigorous input validation and memory safety practices in kernel-level components, as even seemingly minor flaws in integer handling can lead to complete system compromise.