CVE-2011-1991 in Windows
Summary
by MITRE
Multiple untrusted search path vulnerabilities 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 allow local users to gain privileges via a Trojan horse DLL in the current working directory, as demonstrated by a directory that contains a .doc, .rtf, or .txt file, related to (1) deskpan.dll in the Display Panning CPL Extension, (2) EAPHost Authenticator Service, (3) Folder Redirection, (4) HyperTerminal, (5) the Japanese Input Method Editor (IME), and (6) Microsoft Management Console (MMC), aka "Windows Components Insecure Library Loading Vulnerability."
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability described in CVE-2011-1991 represents a critical insecure library loading flaw affecting multiple versions of the microsoft windows operating system. This issue stems from the improper handling of dynamic link library (dll) loading processes within various windows components, creating opportunities for privilege escalation through maliciously placed dll files in the current working directory. The vulnerability affects windows xp service pack 2 and 3, windows server 2003 service pack 2, windows vista service pack 2, windows server 2008 service pack 2 and r2, windows server 2008 r2 service pack 1, and windows 7 gold and service pack 1 operating systems. The flaw manifests when windows components attempt to load dll files without properly validating the search path, allowing attackers to place malicious dlls in directories where legitimate components expect to find their dependencies.
The technical implementation of this vulnerability involves multiple attack vectors across different windows subsystems and applications. The specific components affected include deskpan.dll within the display panning control panel extension, the eaphost authenticator service, folder redirection functionality, hyperterminal application, japanese input method editor, and the microsoft management console. These components all exhibit the same fundamental flaw where the system searches for required libraries in predictable locations including the current working directory before checking system directories. This behavior creates an opportunity for local users to place malicious dll files in directories where these applications execute, causing the system to load the attacker-controlled code instead of legitimate libraries. The vulnerability aligns with common weakness enumeration cwecwe-426 which describes the insecure loading of dynamic libraries, and represents a classic example of a privilege escalation attack vector.
The operational impact of this vulnerability extends beyond simple local privilege escalation to potentially enable complete system compromise. Attackers can leverage this flaw to execute arbitrary code with elevated privileges, potentially allowing them to install backdoors, modify system files, or access sensitive data. The attack requires local system access and involves placing a malicious dll file in the appropriate directory, making it particularly dangerous in environments where users have local access to systems. The vulnerability affects core windows components that are frequently used, increasing the attack surface and potential impact. According to attack technique tactics and techniques framework, this vulnerability maps to technique t1068 privilege escalation and t1546 persistence mechanisms, as attackers can use this to establish persistent access to systems. The impact is particularly severe because these components are often used in administrative functions, making successful exploitation potentially devastating for system security.
Mitigation strategies for CVE-2011-1991 focus on both immediate patching and operational security improvements. Microsoft released security updates addressing this vulnerability in their regular security bulletins, and organizations should ensure all affected systems are properly patched. Additionally, implementing security measures such as disabling unnecessary windows components, using application whitelisting solutions, and enforcing strict directory permissions can reduce the risk of exploitation. System administrators should also consider implementing monitoring for suspicious dll loading activities and establishing secure coding practices for windows applications that avoid insecure library loading patterns. The vulnerability demonstrates the importance of secure coding practices and proper library loading mechanisms, as highlighted in industry standards like the secure coding guidelines from the software engineering institute. Organizations should also implement defense in depth strategies that include regular security assessments and vulnerability scanning to identify similar insecure library loading patterns in custom applications and third-party software.