CVE-2011-1249 in Windows
Summary
by MITRE
The Ancillary Function Driver (AFD) in afd.sys 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 does not properly validate user-mode input, which allows local users to gain privileges via a crafted application, aka "Ancillary Function Driver Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 01/15/2025
The CVE-2011-1249 vulnerability represents a critical privilege escalation flaw within the Ancillary Function Driver component of Microsoft Windows operating systems. This vulnerability exists in the afd.sys kernel driver which handles auxiliary network functions and is particularly concerning because it affects multiple Windows versions including Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008, and Windows 7. The flaw stems from insufficient validation of user-mode input parameters passed to the kernel driver, creating an exploitable condition that allows local attackers to elevate their privileges from standard user level to SYSTEM level access. This type of vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions that can lead to privilege escalation scenarios.
The technical exploitation of this vulnerability occurs when a malicious application crafted by an attacker sends specially formatted input to the AFD driver through the Windows kernel. The driver fails to properly validate these inputs, allowing arbitrary data to be processed without adequate bounds checking or parameter verification. When the kernel driver processes this malformed input, it can cause memory corruption that enables attackers to execute arbitrary code with elevated privileges. This vulnerability operates at the kernel level, meaning that successful exploitation grants the attacker complete control over the system, including the ability to read and write to any memory location, modify system files, and establish persistence mechanisms. The attack vector is local, requiring the attacker to already have a user account on the target system, but the impact is severe as it bypasses standard user privilege boundaries.
The operational impact of CVE-2011-1249 extends beyond simple privilege escalation, as it provides attackers with complete system compromise capabilities. Once elevated to SYSTEM level, attackers can manipulate system configurations, install rootkits, access sensitive data, and potentially use the compromised system as a launch point for further attacks within a network environment. This vulnerability is particularly dangerous in enterprise environments where local access might be obtained through social engineering, compromised accounts, or other initial attack vectors. The vulnerability's presence in so many Windows versions makes it a widespread concern, as organizations with legacy systems or those that have not applied security updates remain at risk. According to MITRE ATT&CK framework, this vulnerability maps to privilege escalation techniques where adversaries leverage kernel-level flaws to gain SYSTEM-level access, representing a critical step in the attack lifecycle that enables further malicious activities.
Mitigation strategies for CVE-2011-1249 primarily focus on immediate patch application, as Microsoft released security updates that address the input validation issues in the AFD driver. Organizations should prioritize applying the relevant security patches from Microsoft's security bulletin MS11-041, which specifically targets this vulnerability. Additionally, implementing defense-in-depth measures such as disabling unnecessary network services, restricting local user account privileges, and monitoring for suspicious kernel-level activity can help reduce the attack surface. System administrators should also consider implementing application whitelisting policies to prevent unauthorized applications from executing and potentially exploiting this vulnerability. Regular security assessments and vulnerability scanning should be conducted to ensure that all affected systems have been properly patched and that no legacy systems remain unpatched. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and the potential consequences of delayed patch management, as this flaw has been widely exploited in the wild since its disclosure.