CVE-2005-3286 in Personal Firewall
Summary
by MITRE
The FWDRV driver in Kerio Personal Firewall 4.2 and Server Firewall 1.1.1 allows local users to cause a denial of service (crash) by setting the PAGE_NOACCESS or PAGE_GUARD protection on the Page Environment Block (PEB), which triggers an exception, aka the "PEB lockout vulnerability."
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Analysis
by VulDB Data Team • 06/29/2025
The vulnerability identified as CVE-2005-3286 represents a critical denial of service flaw within the FWDRV driver component of Kerio Personal Firewall versions 4.2 and Server Firewall 1.1.1. This issue stems from improper handling of memory protection mechanisms within the Windows operating system, specifically involving the Page Environment Block which serves as a crucial data structure containing process-specific information. The vulnerability manifests when local attackers manipulate memory page protection settings to apply PAGE_NOACCESS or PAGE_GUARD flags to the PEB structure, creating a scenario where the firewall driver cannot properly manage memory access controls. The underlying technical flaw resides in the driver's failure to properly validate or handle memory protection changes that affect critical system structures, leading to unhandled exceptions that ultimately result in system crashes.
The operational impact of this vulnerability extends beyond simple service disruption as it provides local attackers with a reliable method to crash the firewall service, effectively rendering the security protection mechanisms ineffective. This creates a significant risk for systems that rely on Kerio Firewall for network protection, as the denial of service can be executed with minimal privileges and does not require special administrative access. The vulnerability operates at the kernel level within the driver context, making it particularly dangerous as it can potentially compromise the integrity of the entire system protection framework. When the PEB lockout occurs, the system experiences a kernel-mode exception that typically results in immediate system instability and requires manual intervention to restore normal operation.
From a cybersecurity perspective, this vulnerability aligns with CWE-248, which addresses "Uncaught Exception in a Driver," and demonstrates how improper exception handling in kernel-mode components can create exploitable conditions. The ATT&CK framework categorizes this as a privilege escalation technique through system service manipulation, where local users can leverage kernel-level flaws to disrupt system operations. The vulnerability also reflects broader concerns related to memory management security, where improper handling of memory protection flags can lead to system instability. Organizations implementing Kerio Firewall solutions face significant risk as this flaw can be exploited by malicious insiders or attackers who gain local access to systems, potentially leading to broader security implications beyond the immediate denial of service condition.
Mitigation strategies for this vulnerability should focus on immediate patch deployment from the vendor, as the flaw exists within the driver's memory management handling logic. System administrators should implement monitoring for unusual memory protection changes and establish baseline configurations that prevent unauthorized modification of critical system structures. Additionally, organizations should consider implementing network segmentation and access controls to limit local user privileges, reducing the attack surface for exploitation. The vulnerability underscores the importance of proper kernel-mode exception handling and memory protection validation in security software, highlighting how seemingly minor implementation flaws can create significant operational risks. Regular security assessments of firewall and security driver components should include memory protection validation testing to identify similar issues before they can be exploited in production environments.