CVE-2010-5151 in Internet Security
Summary
by MITRE
** DISPUTED ** Race condition in avast! Internet Security 5.0.462 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 • 08/07/2024
The vulnerability described in CVE-2010-5151 represents a significant race condition within avast! Internet Security 5.0.462's kernel-mode hook handler implementation on Windows XP systems. This flaw operates at the intersection of operating system security mechanisms and application-level protection systems, creating a pathway for privilege escalation and bypass of security controls. The issue stems from improper synchronization during the execution of kernel-mode hooks, which are designed to monitor and control system calls to prevent malicious activity. When a malicious user-space process attempts to modify memory locations during the execution of a kernel-mode hook handler, the race condition can be exploited to manipulate the execution flow and bypass security protections that would normally block dangerous operations.
The technical exploitation of this vulnerability involves what security researchers have termed argument-switch attacks or KHOBE (Kernel Hook Obfuscation and Execution) techniques. During the execution of a kernel-mode hook handler, legitimate system calls are processed while the hook is active, creating a temporal window where user-space memory modifications can be leveraged to alter the behavior of the hook itself. This race condition allows local attackers to manipulate the arguments passed to kernel-mode functions or redirect execution paths, effectively enabling them to execute code that would normally be blocked by the hook handlers but remains undetected by signature-based malware detection systems. The vulnerability specifically targets the timing and synchronization mechanisms within the avast! security framework's kernel-mode components, exploiting the inherent complexity of multi-layered security architectures where protection mechanisms themselves become attack surfaces.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete bypass of application control and system integrity protections. Attackers can leverage this flaw to execute arbitrary code with kernel-level privileges while evading traditional signature-based detection mechanisms, as the malicious code is not flagged by pattern matching systems but rather exploits the temporal nature of the hook execution. This creates a particularly dangerous scenario where the security software itself becomes a vector for attack, as the protection mechanisms designed to prevent malicious code execution are circumvented through manipulation of their own operational timing. The vulnerability affects Windows XP systems specifically, where the security model and kernel architecture create additional attack surfaces that were not adequately addressed in the hook handler implementation.
Security mitigation strategies for this vulnerability must address both the immediate exploitation techniques and the underlying architectural issues in the hook handler design. System administrators should implement comprehensive monitoring of kernel-mode activities and establish strict access controls to prevent unauthorized modifications to security-critical memory regions. The vulnerability aligns with several ATT&CK framework techniques including privilege escalation through kernel exploitation and defense evasion via hook manipulation. Organizations should consider implementing memory protection mechanisms such as kernel address space layout randomization and exploit prevention technologies to limit the effectiveness of argument-switch attacks. Additionally, regular updates to security software and system patches are essential, as this vulnerability represents a fundamental flaw in the hook handler synchronization that requires architectural changes rather than simple configuration adjustments. The disputed nature of this vulnerability by third parties highlights the complexity of evaluating security flaws in protection mechanisms themselves, where the distinction between legitimate security bypass and inherent design weaknesses requires careful analysis of the attack vectors and their implications for system security posture.
This vulnerability demonstrates the inherent challenges in designing secure kernel-mode protection systems and the potential for security mechanisms to become attack vectors themselves. The race condition exploited here represents a classic case of improper synchronization in security-critical code, where the timing of operations creates exploitable conditions that can be leveraged for privilege escalation and bypass of protection controls. The technical complexity of kernel-mode exploitation combined with the sophisticated nature of modern security software creates environments where traditional security approaches may be insufficient to address all potential attack vectors, particularly when the protection mechanisms themselves contain implementation flaws that can be exploited by determined attackers.