CVE-2018-8271 in Windows
Summary
by MITRE
An information disclosure vulnerability exists in Windows when the Windows bowser.sys kernel-mode driver fails to properly handle objects in memory, aka "Windows Information Disclosure Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers.
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Analysis
by VulDB Data Team • 05/08/2023
The vulnerability identified as CVE-2018-8271 represents a critical information disclosure flaw within the Windows operating system kernel-mode driver component known as bowser.sys. This driver is responsible for implementing the NetBIOS over TCP/IP protocol and managing network browsing services within Windows environments. The flaw manifests when the driver fails to properly handle objects in memory, creating opportunities for unauthorized information exposure. The vulnerability affects multiple Windows versions including Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, and Windows 10 Servers, indicating a widespread impact across the Windows ecosystem. This information disclosure vulnerability falls under the CWE-200 category of "Information Exposure" and aligns with the ATT&CK technique T1082 for system information discovery. The bowser.sys driver operates at kernel level with elevated privileges, making any memory handling flaws particularly dangerous as they can potentially expose sensitive system information to attackers.
The technical implementation of this vulnerability stems from improper memory object handling within the kernel-mode driver. When the bowser.sys driver processes network browsing requests or manages NetBIOS name resolution, it may fail to properly validate or clean memory objects before reuse or release. This improper handling can lead to information leakage through memory corruption patterns or by exposing uninitialized memory contents. Attackers could potentially exploit this weakness to gain access to sensitive data structures, system memory contents, or other confidential information that should remain protected within the kernel space. The vulnerability specifically relates to how the driver manages memory allocation and deallocation processes, particularly when handling network browsing protocol communications. This type of memory management flaw can result in data leakage that might include credentials, system configuration details, or other sensitive information that could aid in further exploitation attempts.
The operational impact of CVE-2018-8271 extends beyond simple information disclosure as it creates potential pathways for more sophisticated attacks. An attacker who successfully exploits this vulnerability could gather information about the target system's network configuration, available resources, or other system details that would normally be protected from casual access. This information could then be leveraged to plan more targeted attacks or to identify additional vulnerabilities within the system. The fact that this affects such a broad range of Windows versions means that organizations across different environments and deployment scenarios could be at risk. The vulnerability's presence in kernel-mode drivers also means that successful exploitation could potentially lead to privilege escalation or system compromise, as kernel-level access provides extensive control over system operations. Network-based attacks could exploit this vulnerability without requiring local system access, making it particularly concerning for enterprise environments where network browsing services are actively used.
Mitigation strategies for CVE-2018-8271 should focus on both immediate patching and network-level protections. Microsoft released security updates for this vulnerability through regular security bulletins, and organizations should ensure all affected systems receive these patches promptly. System administrators should also consider implementing network segmentation and access controls to limit the potential impact of exploitation attempts. Monitoring network traffic for unusual browsing protocol activity or abnormal memory access patterns could help detect exploitation attempts. Additionally, organizations should review their network browsing service configurations and disable unnecessary NetBIOS browsing functionality where possible. The vulnerability's nature as a kernel-mode memory handling issue means that traditional user-mode protections may not be sufficient, requiring careful attention to system-level security controls. Security teams should also implement comprehensive vulnerability management processes that include regular assessment of kernel-mode drivers and their memory handling capabilities to identify similar potential issues. The ATT&CK framework suggests that this vulnerability could be used as part of reconnaissance activities, making proactive monitoring and response capabilities essential for effective defense.