CVE-2005-3240 in Internet Explorer
Summary
by MITRE
Race condition in Microsoft Internet Explorer allows user-assisted attackers to overwrite arbitrary files and possibly execute code by tricking a user into performing a drag-and-drop action from certain objects, such as file objects within a folder view, then predicting the drag action, and re-focusing to a malicious window.
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Analysis
by VulDB Data Team • 04/07/2017
This vulnerability represents a critical race condition flaw in Microsoft Internet Explorer that exploits the browser's handling of drag-and-drop operations within file system contexts. The vulnerability specifically manifests when users perform drag-and-drop actions from file objects within folder views, creating a window of opportunity for malicious actors to manipulate the system. The core technical issue stems from the improper synchronization of file system operations during drag-and-drop interactions, where the browser fails to adequately validate or secure file access during the transition period between drag initiation and drop completion. This race condition creates a temporal gap where attacker-controlled processes can interfere with legitimate file operations, potentially leading to arbitrary file overwrite scenarios.
The operational impact of this vulnerability extends beyond simple file manipulation to potential code execution capabilities, making it particularly dangerous in enterprise environments. Attackers can leverage this weakness by crafting malicious windows or applications that predict and re-focus to specific drag targets, effectively hijacking the drag-and-drop process. When a user performs a legitimate drag operation, the attacker can rapidly switch focus to their malicious window and manipulate the system state, exploiting the window of vulnerability between the drag initiation and the actual file system modification. This user-assisted attack vector requires social engineering to trick victims into performing the initial drag action, but once triggered, the underlying race condition allows for significant system compromise.
From a cybersecurity perspective, this vulnerability aligns with several established frameworks and classifications including CWE-367, which addresses time-of-check to time-of-use (TOCTOU) flaws, and represents a classic example of how seemingly benign user interface interactions can expose critical security weaknesses. The ATT&CK framework categorizes this under privilege escalation and execution techniques, as attackers can leverage this vulnerability to execute arbitrary code with the privileges of the victim user. The vulnerability's exploitation requires minimal technical expertise beyond understanding the drag-and-drop behavior in Windows file systems and the timing characteristics of the race condition. Organizations using older versions of Internet Explorer face heightened risk due to the lack of modern security mitigations such as address space layout randomization and data execution prevention that might otherwise limit the exploit's effectiveness.
Mitigation strategies for this vulnerability primarily focus on immediate patch deployment and user education to prevent social engineering attacks. Microsoft released security updates that addressed the race condition by modifying how Internet Explorer handles drag-and-drop operations and implementing proper synchronization mechanisms. Organizations should implement comprehensive patch management processes to ensure all systems receive security updates promptly. Additional defensive measures include disabling drag-and-drop functionality in high-security environments, implementing application whitelisting policies, and conducting regular security awareness training to help users recognize potentially malicious drag-and-drop scenarios. Network monitoring solutions should also be configured to detect unusual file system access patterns that might indicate exploitation attempts, particularly focusing on rapid file creation or modification events following user interaction with file objects.