CVE-2008-7211 in Ensoniq Pci Es1371 Wdm Driver
Summary
by MITRE
CreativeLabs es1371mp.sys 5.1.3612.0 WDM audio driver, as used in Ensoniq PCI 1371 sound cards and when running on Windows Vista, does not create a Functional Device Object (FDO) to prevent user-moade access to the Physical Device Object (PDO), which allows local users to gain SYSTEM privileges via a crafted IRP request that dereferences a NULL FsContext pointer.
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Analysis
by VulDB Data Team • 12/16/2017
The vulnerability described in CVE-2008-7211 represents a critical privilege escalation flaw within the Creative Labs es1371mp.sys WDM audio driver version 5.1.3612.0, specifically affecting Ensoniq PCI 1371 sound cards operating on Windows Vista systems. This issue stems from improper driver initialization where the audio driver fails to establish a proper Functional Device Object (FDO) structure, creating a security gap that allows malicious local users to exploit the system. The flaw specifically manifests in the driver's handling of IRP (I/O Request Packet) requests, where a crafted IRP can trigger a NULL FsContext pointer dereference, ultimately leading to privilege escalation.
The technical implementation of this vulnerability involves the driver's failure to properly validate and initialize device object structures during the Windows Driver Model (WDM) initialization process. When the es1371mp.sys driver loads, it should create a functional device object that properly manages access controls and device communication channels. However, the absence of this FDO creation means that the underlying Physical Device Object (PDO) remains directly accessible to user-mode applications without proper security boundaries. This architectural oversight creates a pathway for privilege escalation attacks, as the driver's security model relies on proper FDO creation to enforce access control mechanisms.
The operational impact of this vulnerability is severe, as it allows local attackers with standard user privileges to escalate their access level to SYSTEM privileges, which represents the highest level of system access in Windows environments. This privilege escalation occurs through the manipulation of IRP requests that exploit the NULL FsContext pointer dereference, effectively bypassing Windows security mechanisms. The attack vector requires local system access and does not involve network-based exploitation, making it particularly concerning for environments where users might have access to potentially compromised systems. The vulnerability affects Windows Vista systems specifically, though similar issues could potentially exist in other Windows versions with similar driver implementations.
From a cybersecurity perspective, this vulnerability maps directly to CWE-264, which addresses permissions, privileges, and access controls, and represents a classic case of improper privilege management in device drivers. The attack pattern aligns with ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation" and specifically targets driver-level vulnerabilities. The vulnerability demonstrates the critical importance of proper device object initialization in kernel-mode drivers and highlights how seemingly minor implementation flaws can result in complete system compromise. Security researchers and system administrators should consider this vulnerability as part of a broader threat landscape that includes driver-based attacks and privilege escalation techniques.
Mitigation strategies for this vulnerability should include immediate driver updates from Creative Labs to address the FDO creation issue, proper access control enforcement through Windows security policies, and monitoring for unusual IRP request patterns that might indicate exploitation attempts. System administrators should also implement the principle of least privilege, ensuring that user accounts have minimal necessary permissions and that the driver's access controls are properly configured. Additionally, regular security assessments of installed drivers and kernel-mode components should be conducted to identify similar implementation flaws that could potentially lead to privilege escalation attacks. The vulnerability serves as a reminder of the critical need for proper security testing and code review of kernel-mode drivers, particularly those handling hardware device access and I/O operations.