CVE-2007-4967 in Personal Firewall
Summary
by MITRE
Online Armor Personal Firewall 2.0.1.215 does not properly validate certain parameters to System Service Descriptor Table (SSDT) function handlers, which allows local users to cause a denial of service (crash) and possibly gain privileges via unspecified kernel SSDT hooks for Windows Native API functions including (1) NtAllocateVirtualMemory, (2) NtConnectPort, (3) NtCreateFile, (4) NtCreateKey, (5) NtCreatePort, (6) NtDeleteFile, (7) NtDeleteValueKey, (8) NtLoadKey, (9) NtOpenFile, (10) NtOpenProcess, (11) NtOpenThread, (12) NtResumeThread, (13) NtSetContextThread, (14) NtSetValueKey, (15) NtSuspendProcess, (16) NtSuspendThread, and (17) NtTerminateThread.
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Analysis
by VulDB Data Team • 10/31/2017
The vulnerability identified as CVE-2007-4967 represents a critical flaw in Online Armor Personal Firewall version 2.0.1.215 that stems from inadequate parameter validation within the System Service Descriptor Table (SSDT) function handlers. This issue affects the kernel-level operation of Windows native API functions, creating a pathway for local attackers to exploit the firewall's implementation weaknesses. The vulnerability specifically targets the kernel-mode components that handle system service calls, making it particularly dangerous as it operates at the core level of the operating system where privilege escalation and system stability are paramount.
The technical flaw manifests through improper validation of parameters passed to SSDT handlers, which are responsible for intercepting and processing Windows Native API calls. When the firewall attempts to process system calls such as NtAllocateVirtualMemory, NtConnectPort, or NtCreateFile, it fails to adequately validate input parameters before executing kernel-level operations. This validation gap allows malicious input to trigger unexpected behavior in the kernel, potentially leading to system crashes or unauthorized privilege escalation. The vulnerability affects a comprehensive set of 17 critical Windows Native API functions, indicating a systemic issue rather than isolated function flaws. The SSDT hooking mechanism, designed to monitor and control system calls, becomes a vector for exploitation when parameter validation is insufficient.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable privilege escalation attacks. Local users who exploit this vulnerability can cause system crashes through carefully crafted parameter inputs that trigger kernel exceptions, while the same exploitation techniques may allow for elevation of privileges within the kernel context. The affected functions span critical system operations including process management, thread control, file operations, registry access, and memory allocation, providing attackers with extensive control over system resources. This vulnerability particularly impacts systems where Online Armor Personal Firewall is actively running, as the kernel hooks are active and processing system calls continuously. The potential for privilege escalation means that successful exploitation could allow attackers to gain SYSTEM-level privileges, effectively compromising the entire system.
Mitigation strategies for CVE-2007-4967 should focus on immediate patching of the Online Armor Personal Firewall software to address the parameter validation issues in the SSDT handlers. Organizations should implement proper input validation controls at the kernel level and consider disabling unnecessary SSDT hooks that are not essential for firewall functionality. The vulnerability aligns with CWE-129, which addresses improper validation of input parameters, and represents a classic example of kernel-mode exploitation techniques that fall under ATT&CK technique T1068, which covers local privilege escalation through kernel vulnerabilities. System administrators should also consider implementing monitoring for abnormal kernel behavior and ensure that only trusted firewall software is installed on systems. Additionally, the vulnerability demonstrates the importance of proper kernel security practices and the need for comprehensive testing of kernel-mode components before deployment. Organizations should conduct regular security assessments of their firewall implementations and maintain up-to-date patches for all security software to prevent exploitation of similar kernel-level vulnerabilities.