CVE-2003-0887 in ez-ipupdate
Summary
by MITRE
ez-ipupdate 3.0.11b7 and earlier creates insecure temporary cache files, which allows local users to conduct unauthorized operations via a symlink attack on the ez-ipupdate.cache file.
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Analysis
by VulDB Data Team • 06/15/2018
The vulnerability identified as CVE-2003-0887 affects ez-ipupdate version 3.0.11b7 and earlier, presenting a critical security flaw in how the application handles temporary cache files. This issue stems from the application's insecure creation of temporary files during its operation, specifically the ez-ipupdate.cache file that serves as a cache mechanism for IP address updates. The vulnerability enables local attackers to exploit a symlink attack pattern that can lead to unauthorized operations within the system.
The technical flaw manifests when ez-ipupdate creates temporary cache files without proper security measures to prevent symbolic link attacks. When the application generates the ez-ipupdate.cache file, it does not validate or sanitize the file path properly, allowing a local attacker to create a symbolic link with the same name in a location of their choosing. This symlink attack technique exploits the predictable naming and location of temporary files, enabling an attacker to manipulate the cache file contents or redirect the application's operations to malicious targets. The vulnerability is classified under CWE-353, which specifically addresses the weakness of using insecure temporary files in applications, where the application creates temporary files with predictable names and locations that can be manipulated by unauthorized users.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it provides attackers with the ability to perform unauthorized operations within the system. Local users who can create symbolic links can potentially modify the cache contents to inject malicious data, redirect IP update operations to incorrect targets, or even execute arbitrary code if the application processes the cache data without proper validation. This type of attack can be particularly dangerous in environments where ez-ipupdate is used to maintain network connectivity and IP address management, as it could lead to network disruption or unauthorized access to network resources. The attack vector aligns with ATT&CK technique T1059.007 for executing commands through the application's processing of cache files, and T1036.005 for bypassing security controls through symbolic link manipulation.
Mitigation strategies for this vulnerability require immediate patching of the ez-ipupdate application to version 3.0.11b8 or later, which addresses the insecure temporary file creation issue. Organizations should also implement proper file system permissions and ownership controls for temporary directories, ensuring that the application runs with minimal required privileges and that temporary file creation occurs in secure locations. Additionally, the system should be configured to prevent unauthorized symbolic link creation in directories where applications generate temporary files, and regular security audits should verify that applications properly handle temporary file creation and management. This vulnerability demonstrates the importance of following secure coding practices, particularly around temporary file handling, and the necessity of implementing proper input validation and file path sanitization to prevent symbolic link attacks.