CVE-2009-4664 in Firewall Builder
Summary
by MITRE
Firewall Builder 3.0.4, 3.0.5, and 3.0.6, when running on Linux, allows local users to gain privileges via a symlink attack on an unspecified temporary file that is created by the iptables script.
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Analysis
by VulDB Data Team • 05/01/2026
The vulnerability identified as CVE-2009-4664 affects Firewall Builder versions 3.0.4, 3.0.5, and 3.0.6 running on Linux systems, representing a significant privilege escalation risk that exploits a fundamental flaw in temporary file handling mechanisms. This issue stems from the iptables script component of Firewall Builder which creates temporary files without proper security controls, creating an exploitable condition that local attackers can leverage to elevate their privileges from standard user level to root access. The vulnerability specifically manifests through a symlink attack against an unspecified temporary file, demonstrating a classic race condition or insecure temporary file creation pattern that has been documented in numerous security frameworks and standards.
The technical implementation of this vulnerability involves the iptables script's failure to properly secure temporary file creation processes, allowing local users to manipulate the file system by creating symbolic links that redirect the script's operations to malicious targets. This flaw operates under CWE-377, which categorizes insecure temporary file creation practices, and aligns with ATT&CK technique T1068 which covers privilege escalation through local exploits. The vulnerability's exploitation requires the attacker to have local access to the system and the ability to create symbolic links, but once successful, it provides complete system compromise through privilege escalation. The temporary file in question likely exists in a world-writable directory or is created with insufficient permissions, creating a window where attackers can substitute their own files for legitimate temporary files.
The operational impact of CVE-2009-4664 extends beyond simple privilege escalation as it represents a critical security weakness in network security management tools that are typically expected to operate with elevated privileges for configuration management. Organizations using Firewall Builder in production environments face significant risk as this vulnerability can be exploited by any local user to gain root access, potentially compromising entire network security policies and allowing attackers to modify firewall rules, bypass security controls, and establish persistent access. The attack vector is particularly concerning because it targets the very tools designed to protect network security, creating a paradoxical situation where the security infrastructure becomes the attack surface.
Mitigation strategies for this vulnerability require immediate patching of Firewall Builder installations to versions that properly secure temporary file creation processes, typically through the use of secure temporary file creation functions that prevent symbolic link attacks. System administrators should implement additional controls such as ensuring proper file permissions on temporary directories, monitoring for suspicious symbolic link creation patterns, and employing privilege separation techniques that minimize the impact of such vulnerabilities. The remediation process should include verifying that the iptables script no longer creates temporary files in insecure locations and that any temporary file creation follows secure practices that prevent symlink attacks. Organizations should also consider implementing monitoring solutions that can detect attempts to manipulate temporary files or create symbolic links in system directories, as this vulnerability represents a classic example of how insecure temporary file handling can undermine security controls and requires systematic approaches to prevent similar issues in other software components.