CVE-1999-1244 in IPFilter
Summary
by MITRE
IPFilter 3.2.3 through 3.2.10 allows local users to modify arbitrary files via a symlink attack on the saved output file.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability identified as CVE-1999-1244 affects IPFilter versions 3.2.3 through 3.2.10, presenting a significant security risk that stems from improper handling of symbolic links during file operations. This flaw enables local attackers to manipulate the system by creating malicious symbolic links that can redirect file modification operations to unintended targets. The vulnerability specifically manifests when IPFilter saves its output to files, creating opportunities for privilege escalation and data corruption.
The technical implementation of this vulnerability resides in the insufficient validation of file paths and symbolic link resolution within the IPFilter application. When the software processes network filtering rules and attempts to save configuration data to disk, it fails to properly verify whether the target file path represents a legitimate file or a symbolic link pointing elsewhere in the filesystem. This weakness allows attackers to pre-create symbolic links with names that match those used by IPFilter during its operation, thereby redirecting write operations to arbitrary locations on the system. The flaw operates at the file system level and directly violates proper input validation principles that should prevent such path traversal scenarios.
The operational impact of this vulnerability extends beyond simple file modification, potentially enabling attackers to escalate privileges and compromise system integrity. Local users with minimal access can exploit this weakness to overwrite critical system files, configuration data, or even executable programs, depending on the permissions and locations targeted. The attack vector is particularly concerning because it requires minimal privileges and leverages the legitimate operation of the IPFilter service to achieve unauthorized modifications. This type of vulnerability aligns with CWE-59, which describes improper link resolution without limit checks, and represents a classic example of a race condition vulnerability where the timing of file creation and access operations creates exploitable conditions.
Mitigation strategies for this vulnerability should focus on immediate patching of affected IPFilter versions to the latest available releases that address the symbolic link handling issue. System administrators should implement proper file system permissions and access controls to limit the ability of local users to create symbolic links in directories where IPFilter operations occur. Additionally, the application should be configured to perform explicit validation of file paths and symbolic link resolution before any write operations are performed. Organizations should also consider implementing monitoring solutions that can detect suspicious file modification patterns and unusual symbolic link creation activities. This vulnerability demonstrates the importance of proper input validation and file system security practices as outlined in various security frameworks, including those addressing privilege escalation and file system integrity protection. The attack scenario aligns with techniques described in the ATT&CK framework under privilege escalation tactics, specifically focusing on the abuse of file system permissions and local privilege escalation methods.