CVE-2011-1227 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 SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows local users to gain privileges via a crafted application that triggers a NULL pointer dereference, a different vulnerability than other "Vulnerability Type 2" CVEs listed in MS11-034, aka "Win32k Null Pointer De-reference Vulnerability."
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Analysis
by VulDB Data Team • 05/15/2025
The CVE-2011-1227 vulnerability represents a critical privilege escalation flaw within the Windows kernel-mode driver subsystem, specifically targeting the win32k.sys component that manages graphical user interface elements and windowing operations. This vulnerability exists in multiple Windows operating systems including Windows xp sp2 and sp3, windows server 2003 sp2, windows vista sp1 and sp2, windows server 2008 gold and sp2, windows server 2008 r2 and r2 sp1, and windows 7 gold and sp1. The flaw stems from a NULL pointer dereference condition in the kernel-mode driver that handles user interface operations, creating a scenario where malicious applications can trigger unauthorized privilege elevation.
The technical implementation of this vulnerability involves a crafted application that deliberately manipulates the win32k.sys driver to access memory locations that have not been properly initialized or validated. When the driver attempts to dereference a NULL pointer during legitimate user interface operations, it creates an exploitable condition that allows local attackers to execute arbitrary code with elevated privileges. This mechanism differs from other vulnerabilities classified as "Vulnerability Type 2" in ms11-034, indicating that while related to kernel-mode graphics handling, this specific flaw operates through a distinct exploitation vector. The vulnerability is categorized under common weakness enumeration cw00000001, which covers null pointer dereference conditions in software systems.
From an operational perspective, this vulnerability presents a significant risk to system security as it allows local users to escalate their privileges without requiring authentication or network access. Attackers can leverage this flaw by running specially crafted applications that trigger the NULL pointer dereference within the win32k.sys driver, potentially enabling them to execute code with system-level privileges. The impact extends beyond individual system compromise to potentially enable broader network infiltration, as attackers can establish persistent access and move laterally within compromised environments. This vulnerability particularly affects enterprise environments where multiple users may have local access to systems, making it a preferred target for attackers seeking to establish footholds within networks.
The recommended mitigations for CVE-2011-1227 include immediate deployment of microsoft security patches and updates that address the specific NULL pointer dereference in win32k.sys. System administrators should prioritize patch management across all affected windows operating systems, ensuring that all instances of windows xp sp2 and sp3, windows server 2003 sp2, windows vista sp1 and sp2, windows server 2008 gold and sp2, windows server 2008 r2 and r2 sp1, and windows 7 gold and sp1 are updated. Additionally, implementing security measures such as user access controls, limiting local user privileges, and monitoring for suspicious process behavior can help reduce the attack surface. Organizations should also consider implementing application whitelisting policies and maintaining up-to-date intrusion detection systems to identify potential exploitation attempts. The vulnerability aligns with attack technique tt0001 in the attack tactic framework, which focuses on privilege escalation through kernel-mode exploits, making it a critical target for defensive security measures and incident response protocols.