CVE-2011-0038 in Internet Explorer
Summary
by MITRE
Untrusted search path vulnerability in Microsoft Internet Explorer 8 might allow local users to gain privileges via a Trojan horse IEShims.dll in the current working directory, as demonstrated by a Desktop directory that contains an HTML file, aka "Internet Explorer Insecure Library Loading Vulnerability."
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability identified as CVE-2011-0038 represents a critical untrusted search path issue affecting Microsoft Internet Explorer 8 that enables local privilege escalation through malicious DLL loading techniques. This flaw resides in the way Internet Explorer handles dynamic library loading during web content rendering processes, specifically when the browser encounters HTML content that triggers loading of system libraries. The vulnerability is particularly dangerous because it leverages the trust model that Internet Explorer employs when searching for required libraries, allowing attackers to place malicious code in predictable locations where the browser will automatically load it without proper validation. The attack vector involves placing a specially crafted Trojan horse IEShims.dll file in the current working directory, which typically includes common user directories such as the Desktop, making exploitation straightforward for local attackers who can manipulate the user's environment.
The technical implementation of this vulnerability stems from Internet Explorer 8's failure to properly validate library paths during dynamic link library loading operations. When processing HTML content that references certain system components, the browser performs a search through the system's PATH environment variable and current working directory to locate required libraries. This search mechanism does not adequately distinguish between legitimate system libraries and malicious substitutes, allowing an attacker to place a crafted IEShims.dll file in a directory that Internet Explorer will prioritize during the loading process. The vulnerability is categorized under CWE-427 Uncontrolled Search Path Element, which specifically addresses situations where applications search for libraries or executables in directories that can be manipulated by attackers. This weakness creates a fundamental trust issue where the application's security model relies on the assumption that all libraries in the search path are legitimate, which is easily subverted by local privilege attackers.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass broader security implications for enterprise environments where users may have local access to systems running Internet Explorer 8. Local attackers who can place files in the user's working directory can execute arbitrary code with the privileges of the logged-in user, potentially leading to complete system compromise. The attack requires minimal sophistication and can be executed through simple file placement, making it particularly dangerous in environments where users frequently interact with web content or have access to directories where the browser might search for libraries. This vulnerability aligns with ATT&CK technique T1068 which describes the use of local privilege escalation techniques, and more specifically with T1574 which covers hijacking execution flow through dynamic link library loading. The vulnerability's exploitation does not require network access or complex attack chains, making it particularly attractive to threat actors seeking to establish persistent access or escalate privileges within compromised systems.
Mitigation strategies for CVE-2011-0038 should focus on both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities. Microsoft addressed this issue through security updates that modified the library loading behavior in Internet Explorer 8 to implement more strict path validation and prevent loading of libraries from untrusted locations. Organizations should ensure that all systems running Internet Explorer 8 have received the applicable security patches and that the browser is updated to supported versions that do not contain this vulnerability. Additional defensive measures include implementing least privilege principles for user accounts, restricting write access to common directories such as Desktop, and employing application whitelisting solutions that prevent execution of unauthorized DLL files. The vulnerability demonstrates the critical importance of secure coding practices in library loading mechanisms and highlights the necessity for applications to validate library sources and implement proper sandboxing techniques. System administrators should also monitor for suspicious file placement activities in user directories and implement security awareness training to help users understand the risks associated with placing unknown files in potentially accessible locations.