CVE-2015-0084 in Windows
Summary
by MITRE
The Task Scheduler in Microsoft Windows 7 SP1, Windows Server 2008 R2 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 does not properly constrain impersonation levels, which allows local users to bypass intended restrictions on launching executable files via a crafted task, aka "Task Scheduler Security Feature Bypass Vulnerability."
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Analysis
by VulDB Data Team • 12/02/2024
The Task Scheduler component in Microsoft Windows operating systems contains a critical security flaw that allows local attackers to circumvent intended access controls and execute arbitrary code with elevated privileges. This vulnerability affects multiple versions of Windows including Windows 7 SP1, Windows Server 2008 R2 SP1, Windows 8, Windows 8.1, Windows Server 2012, and Windows RT. The issue stems from improper handling of impersonation levels within the task scheduling mechanism, creating a pathway for privilege escalation attacks.
The technical root cause of this vulnerability lies in how the Task Scheduler component manages user context and impersonation during task execution. When a task is scheduled to run, the system should properly constrain the impersonation level to prevent unauthorized privilege escalation. However, the flawed implementation allows local users to manipulate the impersonation context in such a way that they can bypass the intended security boundaries. This occurs because the system fails to validate or restrict the impersonation levels appropriately, enabling attackers to launch executable files with higher privileges than intended.
From an operational perspective, this vulnerability represents a significant risk to system security as it allows local users to perform privilege escalation attacks without requiring remote access or complex exploitation techniques. Attackers can craft malicious tasks that exploit the impersonation level bypass to execute code with elevated privileges, potentially leading to complete system compromise. The vulnerability is particularly dangerous because it requires minimal user interaction and can be exploited by any local user with access to the system, making it a common target for both malicious actors and automated attack tools.
The impact of this vulnerability aligns with CWE-269, which addresses "Improper Privilege Management" in software systems. This weakness specifically manifests in the failure to properly manage user privileges within the Windows Task Scheduler component, creating a security gap that can be exploited by attackers. The vulnerability also maps to several ATT&CK techniques including privilege escalation through scheduled tasks and abuse of system permissions. Organizations running affected Windows versions face substantial risk of unauthorized system access and potential data breaches when this vulnerability remains unpatched.
Mitigation strategies should include immediate installation of Microsoft security updates that address the impersonation level validation issues in the Task Scheduler component. System administrators should also implement additional security controls such as restricting local user access to task scheduler functionality, monitoring scheduled tasks for suspicious activity, and ensuring that only trusted users have the ability to create or modify scheduled tasks. Network segmentation and principle of least privilege configurations can further reduce the attack surface and limit potential exploitation of this vulnerability across the enterprise environment.