CVE-2010-5175 in PrivateFirewall
Summary
by MITRE
** DISPUTED ** Race condition in PrivateFirewall 7.0.20.37 on Windows XP allows local users to bypass kernel-mode hook handlers, and execute dangerous code that would otherwise be blocked by a handler but not blocked by signature-based malware detection, via certain user-space memory changes during hook-handler execution, aka an argument-switch attack or a KHOBE attack. NOTE: this issue is disputed by some third parties because it is a flaw in a protection mechanism for situations where a crafted program has already begun to execute.
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Analysis
by VulDB Data Team • 07/03/2024
The vulnerability described in CVE-2010-5175 represents a significant race condition within the kernel-mode hook handler mechanism of PrivateFirewall version 7.0.20.37 running on Windows XP systems. This flaw operates at the intersection of kernel security and user-mode exploitation techniques, creating a pathway for privilege escalation and bypass of security controls that are designed to protect against malicious code execution. The vulnerability specifically targets the timing window during which kernel-mode hook handlers process user-space memory modifications, allowing local attackers to manipulate execution flow and circumvent protective measures that would normally block dangerous operations.
The technical implementation of this vulnerability leverages a classic race condition attack pattern where the timing of memory operations during hook handler execution creates a window of opportunity for malicious code manipulation. This attack vector, sometimes referred to as an argument-switch attack or KHOBE (Kernel Hook Obfuscation Exploitation) attack, exploits the fundamental mismatch between user-mode memory changes and kernel-mode protection mechanisms. During the execution of hook handlers, when kernel code is processing user-space memory modifications, an attacker can strategically alter memory contents to redirect execution paths or modify parameters that would normally be validated by the security system.
From an operational impact perspective, this vulnerability demonstrates a critical weakness in layered security approaches where protection mechanisms rely on temporal consistency between user-mode and kernel-mode operations. The attack allows local users to effectively bypass kernel-mode security controls that are designed to monitor and block malicious activities, including those that would normally be detected by signature-based malware detection systems. This creates a scenario where sophisticated malware could execute code that would otherwise be blocked by the firewall's hook handlers but remains undetected by traditional signature-based defenses due to the timing-based bypass mechanism.
The vulnerability's disputed nature stems from the fact that it operates within a protection mechanism designed to defend against scenarios where malicious programs have already begun execution, rather than preventing initial code injection or execution. This places the vulnerability in a grey area where traditional security models must account for the possibility that attackers may already have compromised system access and are attempting to evade additional security controls. The attack requires local system access and leverages the specific timing characteristics of the Windows kernel's hook handling mechanism, making it a sophisticated but not easily exploitable vulnerability that requires deep understanding of kernel internals and timing-based attack techniques.
Security mitigations for this vulnerability should focus on strengthening the consistency checks within kernel-mode hook handlers and implementing additional validation mechanisms that prevent memory manipulation during critical execution windows. Organizations should consider updating to newer versions of security software that address these timing-based vulnerabilities and implement monitoring for unusual kernel-mode behavior patterns. The vulnerability highlights the importance of considering timing-based attack vectors in kernel security design and demonstrates how even sophisticated protection mechanisms can be undermined by race condition exploitation techniques that are well-established in the cybersecurity community and documented in frameworks such as the attack tactics described in the MITRE ATT&CK framework under privilege escalation and defense evasion categories.