CVE-2012-1848 in Windows
Summary
by MITRE
win32k.sys in the kernel-mode drivers in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2, R2, and R2 SP1, Windows 7 Gold and SP1, and Windows 8 Consumer Preview does not properly handle user-mode input passed to kernel mode, which allows local users to gain privileges via a crafted application, aka "Scrollbar Calculation Vulnerability."
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Analysis
by VulDB Data Team • 03/24/2021
The CVE-2012-1848 vulnerability represents a critical privilege escalation flaw within the Windows kernel-mode driver subsystem, specifically affecting the win32k.sys component that manages graphical user interface elements. This vulnerability falls under the CWE-125 weakness category, which describes out-of-bounds read conditions in kernel-mode drivers, and aligns with ATT&CK technique T1068 for privilege escalation through kernel exploits. The flaw manifests when the kernel-mode driver fails to properly validate user-mode input that is passed to kernel mode, creating a pathway for malicious applications to execute arbitrary code with elevated privileges. The vulnerability is particularly concerning because it affects multiple versions of Windows operating systems spanning from Windows xp through Windows 8, making it a widespread target for attackers seeking to establish persistent access to compromised systems.
The technical mechanism behind this vulnerability involves the improper handling of scrollbar calculation parameters within the win32k.sys driver. When a user interacts with graphical elements such as scrollbars, the system passes user-mode input data to kernel-mode components for processing. The flaw occurs during this transition where insufficient bounds checking allows crafted input to cause memory corruption in kernel space. Attackers can exploit this by creating a malicious application that carefully constructs scrollbar parameters to trigger the overflow condition, ultimately leading to privilege escalation. The vulnerability specifically targets the interaction between user-mode applications and kernel-mode drivers, leveraging the inherent trust relationship between these components to bypass security boundaries. This type of vulnerability is classified as a kernel-mode privilege escalation vulnerability and represents a significant concern for system security.
The operational impact of CVE-2012-1848 is substantial as local attackers who can execute code on a target system can leverage this vulnerability to gain SYSTEM-level privileges, effectively providing complete control over the compromised machine. Once successfully exploited, attackers can perform actions such as installing malware, modifying system files, creating new user accounts, and accessing sensitive data without detection. The vulnerability's exploitation requires only local access to the system, making it particularly dangerous in environments where user accounts have elevated privileges or where social engineering attacks can trick users into running malicious applications. Organizations running affected Windows versions face significant risk as this vulnerability can be exploited through various attack vectors including malicious email attachments, drive-by downloads, or compromised legitimate software. The widespread nature of affected operating systems means that countless systems remain vulnerable, potentially creating large-scale attack surfaces for threat actors.
Mitigation strategies for CVE-2012-1848 should focus on both immediate remediation and long-term security improvements. Microsoft released security patches through the regular update cycle that address this vulnerability by implementing proper bounds checking in the win32k.sys driver. Organizations should prioritize immediate deployment of the relevant security updates, particularly for systems running unsupported operating systems where patches may not be available. System administrators should also implement additional security controls such as enabling address space layout randomization, disabling unnecessary services, and implementing application whitelisting to prevent exploitation attempts. The vulnerability demonstrates the importance of kernel-mode input validation and proper security boundaries between user and kernel space, reinforcing the need for comprehensive security testing of driver components. Regular security assessments and vulnerability scanning should include checks for outdated kernel components, while security monitoring should focus on unusual privilege escalation attempts that might indicate exploitation of similar vulnerabilities.