CVE-2010-3337 in Office
Summary
by MITRE
Untrusted search path vulnerability in Microsoft Office 2007 SP2 and 2010 allows local users to gain privileges via a Trojan horse DLL in the current working directory, aka "Insecure Library Loading Vulnerability." NOTE: this might overlap CVE-2010-3141 and CVE-2010-3142.
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Analysis
by VulDB Data Team • 09/29/2021
The vulnerability described in CVE-2010-3337 represents a critical insecure library loading flaw affecting Microsoft Office 2007 Service Pack 2 and Office 2010 installations. This issue stems from the improper handling of dynamic link library (dll) loading mechanisms within the Microsoft Office application suite, creating a pathway for privilege escalation attacks through malicious code injection. The vulnerability specifically manifests when Office applications attempt to load dynamic libraries from the current working directory without proper validation of the library source or integrity checks. This behavior aligns with CWE-427, which describes uncontrolled search path dependencies, and CWE-428, addressing untrusted search path vulnerabilities. The flaw enables attackers to place a malicious Trojan horse dll file in the current working directory where a legitimate Office application is executing, allowing the malicious code to be loaded and executed with the privileges of the targeted user. This type of vulnerability is particularly dangerous because it leverages the trust relationship that applications maintain with their working directories, which are typically considered safe execution environments. The attack vector exploits the Windows dynamic loading mechanism where applications search for required libraries in a specific order, including the current working directory, which is often the first location checked. This vulnerability falls under the ATT&CK technique T1068, which describes the use of local privilege escalation techniques through the exploitation of insecure library loading, and T1546, covering the execution of malicious code through dynamic link library injection.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data theft. When a local attacker successfully places a malicious dll in the working directory of an Office application, the malicious code executes with the same privileges as the legitimate user, potentially allowing access to sensitive documents, network resources, or system information. The vulnerability's persistence across multiple Office versions indicates a fundamental flaw in the application's library loading architecture that was not adequately addressed in the security updates provided at the time. This creates a widespread risk profile as the attack can be executed across numerous installations without requiring specialized knowledge of specific application behaviors or system configurations. The vulnerability's exploitation does not require network connectivity or complex attack chains, making it particularly dangerous in enterprise environments where users may inadvertently execute malicious Office documents. The potential for privilege escalation to SYSTEM level access exists when users run Office applications with elevated privileges, though the default behavior of Office applications typically runs with standard user permissions, limiting the scope of potential compromise.
Mitigation strategies for CVE-2010-3337 should focus on both immediate defensive measures and long-term architectural improvements. Organizations should implement strict directory permissions and access controls to prevent unauthorized dll placement in common working directories where Office applications execute. The principle of least privilege should be enforced by ensuring that Office applications run with minimal required permissions and that users do not have write access to directories containing legitimate Office installation files. Security awareness training should emphasize the dangers of executing unknown or untrusted Office documents, as these files often serve as the initial vector for placing malicious dll files in the working directory. Application whitelisting solutions can provide additional protection by restricting which dll files can be loaded and executed on systems, effectively neutralizing the impact of malicious dll placement. Microsoft's official patch for this vulnerability addressed the core library loading issue by implementing proper validation of library sources and modifying the search path order to prioritize system directories over the current working directory. Regular security updates and patch management processes should be enforced to ensure that all Office installations receive the necessary security fixes. The vulnerability also highlights the importance of secure coding practices and the need for developers to avoid relying on insecure search path mechanisms, as outlined in various secure coding guidelines and standards. Network segmentation and monitoring solutions should be implemented to detect suspicious dll loading activities and unauthorized file placement attempts that may indicate exploitation attempts.