CVE-2017-0244 in Windows
Summary
by MITRE
The kernel in Windows Server 2008 SP2 and R2 SP1, and Windows 7 SP1 allows locally authenticated attackers to gain privileges via a crafted application, or in Windows 7 for x64-based systems, cause denial of service, aka "Windows Kernel Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 12/23/2020
This vulnerability represents a critical privilege escalation flaw in the Windows kernel that affects multiple server and desktop operating systems including Windows Server 2008 SP2 and R2 SP1, as well as Windows 7 SP1. The vulnerability stems from improper validation of kernel-mode objects, specifically related to how the kernel handles certain object types during privilege checking operations. Attackers can exploit this weakness by crafting a malicious application that leverages the flawed kernel object validation mechanism to elevate their privileges from standard user level to kernel level access. The vulnerability is particularly concerning because it requires only local authentication, meaning an attacker who has already gained access to a user account on the system can potentially escalate their privileges without requiring additional credentials or complex attack vectors.
The technical implementation of this vulnerability involves a race condition or improper object reference handling within the kernel's privilege checking subsystem. When legitimate applications attempt to access certain kernel objects, the system fails to properly validate the object's security attributes or access rights, allowing malicious code to manipulate these objects and gain unauthorized access to kernel-level resources. This flaw is categorized under CWE-264 as "Permissions, Privileges and Access Controls" and specifically relates to improper handling of kernel objects. The vulnerability can be exploited through various kernel object manipulation techniques, including but not limited to object type confusion, use-after-free conditions, or improper access control checks that allow unauthorized code execution in kernel mode.
The operational impact of this vulnerability extends beyond simple privilege escalation, as successful exploitation can provide attackers with complete system compromise capabilities. Once elevated to kernel privileges, attackers can bypass all operating system security mechanisms, modify system files, install rootkits, access all user data, and establish persistent backdoors. The vulnerability affects both 32-bit and 64-bit systems but is particularly significant on x64-based Windows 7 systems where the denial of service component can be leveraged to disrupt system operations. Organizations running affected systems face severe security implications, as this vulnerability can be exploited by malware or attackers who have already gained initial access to a system through other means such as phishing attacks or unpatched applications.
Mitigation strategies for this vulnerability should include immediate deployment of Microsoft security patches as part of comprehensive vulnerability management programs. System administrators should prioritize patching critical vulnerabilities like this one through automated update mechanisms or manual deployment procedures. Additional defensive measures include implementing least privilege principles, monitoring for suspicious kernel-level activity through endpoint detection and response tools, and employing application whitelisting solutions to prevent execution of malicious code. The vulnerability aligns with several ATT&CK techniques including privilege escalation through kernel exploits and persistence mechanisms. Organizations should also consider implementing network segmentation and monitoring for unusual privilege escalation events that could indicate exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify systems running affected operating systems and ensure timely patch deployment across all endpoints.