CVE-2006-4092 in Internet Explorer
Summary
by MITRE
Simpliciti Locked Browser does not properly limit a user s actions to ones within the intended Internet Explorer environment, which allows local users to perform unauthorized actions by visiting a web site that executes a JavaScript window.blur loop to remove focus from the browser window, then pressing CTRL-SHIFT-ESC to invoke the Task Manager.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/20/2017
The vulnerability identified as CVE-2006-4092 affects Simpliciti Locked Browser, a restricted browsing environment designed to limit user interactions to prevent unauthorized access to system resources. This security flaw represents a significant bypass of the intended security boundaries within the locked browser implementation. The vulnerability stems from the browser's inadequate enforcement of user action limitations, creating a pathway for local attackers to escape the controlled environment and execute privileged operations. The issue manifests through a specific technique involving JavaScript manipulation that exploits the browser's focus management mechanisms.
The technical implementation of this vulnerability relies on the ability of malicious web content to manipulate the browser window focus through JavaScript execution. When a user visits a specially crafted website, the JavaScript code initiates a window.blur loop that continuously removes focus from the browser window. This focus manipulation creates an opportunity for the attacker to invoke system-level shortcuts that are normally restricted within the locked browser environment. The specific key combination CTRL-SHIFT-ESC triggers the Windows Task Manager, which provides access to system processes and potentially elevated privileges. This technique demonstrates a fundamental flaw in the browser's isolation mechanism and represents a classic case of privilege escalation through focus manipulation.
The operational impact of this vulnerability extends beyond simple unauthorized access to system resources. Attackers can leverage this flaw to gain visibility into running processes, potentially access sensitive system information, and in some cases escalate privileges to execute malicious code with elevated permissions. The vulnerability affects local users who visit compromised websites, meaning that no network-based attacks are required to exploit this flaw. This makes the vulnerability particularly dangerous in environments where users might encounter malicious content through email attachments, web browsing, or other means of content delivery. The attack vector demonstrates how seemingly benign browser features can be exploited to bypass security controls, highlighting the importance of comprehensive sandboxing and focus management in restricted environments.
This vulnerability aligns with CWE-254, which addresses security weaknesses related to improper privilege management and inadequate access control mechanisms. The flaw represents a failure in implementing proper security boundaries within the browser environment, allowing unauthorized system interactions that should be restricted. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and defense evasion, specifically leveraging the Task Manager to bypass security controls. The attack pattern demonstrates how attackers can exploit browser focus management to gain elevated privileges, which corresponds to ATT&CK technique T1059 for execution through scripting and T1068 for bypassing security controls. Organizations implementing locked browser environments must consider the broader implications of focus management and ensure that all user interactions are properly constrained to prevent similar bypasses.
Mitigation strategies for this vulnerability should focus on implementing comprehensive browser isolation mechanisms that prevent external focus manipulation and restrict access to system-level shortcuts. The most effective approach involves modifying the locked browser environment to prevent JavaScript from manipulating window focus in ways that could lead to system-level access. Organizations should also implement network-level controls to prevent access to potentially malicious websites and ensure that the browser environment properly handles focus management. Regular security assessments of locked browser implementations are essential to identify similar vulnerabilities that could allow unauthorized system access through focus manipulation or other user interaction bypass techniques. The vulnerability underscores the critical importance of proper sandboxing and access control implementation in restricted browsing environments, particularly those designed to prevent unauthorized system interactions.