CVE-2016-7218 in Windows
Summary
by MITRE
Bowser.sys in the kernel-mode drivers in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, and 1607, and Windows Server 2016 allows local users to obtain sensitive information via a crafted application, aka "Windows Bowser.sys Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 09/30/2022
The vulnerability identified as CVE-2016-7218 affects the Bowser.sys kernel-mode driver component within Microsoft Windows operating systems across multiple versions including Vista SP2 through Windows 10 1607 and Windows Server 2016. This represents a critical information disclosure flaw that resides in the kernel-mode drivers responsible for network browsing services. The vulnerability specifically impacts systems running Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, and 1607 operating systems. The flaw allows local attackers to extract sensitive information through the exploitation of improper input validation mechanisms within the Bowser.sys driver.
The technical root cause of this vulnerability stems from inadequate validation of user-supplied data within the kernel-mode driver context. When a crafted application interacts with the Bowser.sys driver, it can trigger a condition where sensitive kernel memory contents are inadvertently exposed to user-mode applications. This occurs due to insufficient bounds checking and improper handling of input parameters that flow through the driver's processing pipeline. The vulnerability is classified as a memory disclosure issue that operates at the kernel level, making it particularly dangerous as it can potentially expose system-level information including credentials, encryption keys, or other confidential data stored in kernel memory. The flaw represents a classic case of improper input validation that violates security principles outlined in CWE-125, which addresses out-of-bounds read conditions.
From an operational perspective, this vulnerability presents significant risk to organizations as it requires only local system access to exploit, making it particularly dangerous in environments where privilege escalation or lateral movement is possible. Attackers can leverage this information disclosure to gain insights into system memory structures, potentially enabling more sophisticated attacks such as privilege escalation or targeted exploitation of other vulnerabilities. The impact extends beyond simple information disclosure as the leaked memory contents may contain sensitive data that could be used to craft more effective attacks against the target system. This vulnerability aligns with ATT&CK technique T1003.001 for OS credential dumping and T1005 for data from local system, as it provides attackers with access to memory contents that may contain sensitive information.
The exploitation of this vulnerability requires local system access and typically involves crafting a malicious application that can interact with the vulnerable Bowser.sys driver. Attackers can utilize the information disclosure to potentially identify system memory layouts, extract credentials, or discover other sensitive data that could be leveraged in subsequent attacks. The vulnerability affects both 32-bit and 64-bit versions of the supported operating systems, making it broadly applicable across different deployment scenarios. Organizations should note that the vulnerability exists in multiple Windows versions, requiring comprehensive patch management across their entire infrastructure. The information disclosure aspect of this vulnerability makes it particularly concerning as it can provide attackers with the foundational knowledge needed to develop more targeted attacks against the system.
Mitigation strategies for this vulnerability include immediate deployment of Microsoft security updates that address the Bowser.sys driver information disclosure issue. System administrators should prioritize patching all affected Windows versions, particularly those running in enterprise environments where local access might be more easily obtained by malicious actors. Additional protective measures include implementing least privilege principles to limit local user access, monitoring for suspicious process activity related to kernel-mode driver interactions, and conducting regular security assessments to identify potential exploitation attempts. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of local privilege escalation attempts that might result from information disclosure. The vulnerability highlights the importance of kernel-mode driver security and proper input validation mechanisms in preventing information disclosure attacks that could compromise entire systems.