CVE-2011-1247 in Windows
Summary
by MITRE
Untrusted search path vulnerability in the Microsoft Active Accessibility component in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows local users to gain privileges via a Trojan horse DLL in the current working directory, aka "Active Accessibility Insecure Library Loading Vulnerability."
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Analysis
by VulDB Data Team • 11/23/2021
The CVE-2011-1247 vulnerability represents a critical untrusted search path issue within Microsoft Active Accessibility component across multiple windows operating systems. This vulnerability specifically affects Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2, and Windows 7 Gold and SP1 versions. The flaw resides in how the Active Accessibility component handles library loading operations, creating a path traversal risk that enables malicious actors to execute arbitrary code with elevated privileges.
The technical exploitation of this vulnerability occurs through a Trojan horse DLL placement attack in the current working directory of the targeted system. When the Active Accessibility component attempts to load necessary libraries, it follows a predictable search order that includes the current working directory before system directories. This insecure library loading behavior allows an attacker to place a malicious DLL with the same name as a legitimate system library in the current working directory, causing the system to load and execute the attacker-controlled code instead of the intended system library. This vulnerability directly maps to CWE-427 Uncontrolled Search Path Element and CWE-428 Uncontrolled Search Path Element, both of which address insecure library loading practices.
The operational impact of this vulnerability is significant as it provides local users with privilege escalation capabilities, potentially allowing attackers to elevate their access level from standard user to system administrator. The attack vector is particularly concerning because it requires minimal privileges to exploit and can be executed through simple file placement attacks. The vulnerability's persistence across multiple windows versions makes it a widespread concern for organizations maintaining legacy systems. From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1068 Exploitation for Privilege Escalation and T1574 Hijacking Execution Flow, demonstrating how insecure library loading can be leveraged for system compromise.
Mitigation strategies for CVE-2011-1247 should focus on immediate system hardening measures including implementing proper access controls, restricting write permissions on system directories, and ensuring that the current working directory is not prioritized in library search paths. Organizations should also implement application whitelisting policies and regularly audit system libraries to detect unauthorized modifications. Microsoft addressed this vulnerability through security updates that modified the Active Accessibility component's library loading behavior, ensuring that system directories are prioritized over the current working directory during library resolution processes. Additionally, administrators should consider implementing security awareness training to prevent accidental exploitation through social engineering attacks that might place malicious DLLs in targeted directories.