CVE-2003-0438 in eldav
Summary
by MITRE
eldav WebDAV client for Emacs, version 0.7.2 and earlier, allows local users to create or overwrite arbitrary files via a symlink attack on temporary files.
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Analysis
by VulDB Data Team • 06/28/2021
The vulnerability identified as CVE-2003-0438 affects eldav, a WebDAV client implementation for the Emacs text editor. This security flaw exists in versions 0.7.2 and earlier, representing a significant concern for users who employ this client for WebDAV operations. The vulnerability stems from inadequate handling of temporary files during the WebDAV client's operation, creating opportunities for malicious local users to exploit the system through symbolic link manipulation techniques. This type of vulnerability falls under the category of insecure temporary file handling, which has been consistently identified as a critical security weakness across various software platforms and operating systems.
The technical implementation of this vulnerability involves the eldav client creating temporary files during WebDAV operations without proper security measures to prevent symbolic link attacks. When a local user can predict or influence the creation of temporary files, they can establish symbolic links that point to sensitive system files or locations where they wish to create or overwrite content. This attack vector allows an attacker to bypass normal file permissions and access controls, potentially leading to privilege escalation or unauthorized data modification. The flaw specifically manifests when the client does not properly validate or secure temporary file creation processes, making it susceptible to race conditions and symlink-based attacks that are commonly documented in security literature.
The operational impact of this vulnerability extends beyond simple file manipulation, as it can potentially enable more severe security consequences depending on the system configuration and user privileges. Local users who exploit this vulnerability could gain the ability to overwrite critical system files, create malicious files in sensitive locations, or modify configuration files that affect the WebDAV client's behavior. This type of attack can be particularly dangerous in multi-user environments where different users share the same system resources, as it may allow privilege escalation or persistent backdoor creation. The vulnerability's exploitation does not require network access or remote system compromise, making it particularly concerning as it can be exploited entirely from within the local system environment.
The security implications of CVE-2003-0438 align with common attack patterns documented in the MITRE ATT&CK framework, particularly under the techniques related to privilege escalation and persistence mechanisms. This vulnerability demonstrates how insecure temporary file handling can be leveraged for unauthorized system access, which corresponds to CWE-352, or Cross-Site Request Forgery, and more specifically CWE-377, which addresses insecure temporary files. The attack scenario involves a local user manipulating the file system to redirect file operations to unintended locations, which is a classic example of a symlink attack that has been documented in numerous security advisories and vulnerability assessments over the years. Organizations using affected versions of eldav should consider this vulnerability as part of their broader security posture assessment, particularly in environments where multiple users share system resources or where the WebDAV client is used with elevated privileges.
Mitigation strategies for this vulnerability primarily involve upgrading to a patched version of the eldav WebDAV client that properly handles temporary file creation and validation. System administrators should ensure that all instances of the affected software are updated to versions that implement secure temporary file handling practices, such as creating temporary files with unique names and proper permissions, or using atomic file creation methods that prevent symlink attacks. Additionally, implementing proper file system permissions and monitoring for unexpected file modifications can help detect potential exploitation attempts. The vulnerability also highlights the importance of secure coding practices, particularly around temporary file handling, which should be addressed through code reviews and security testing processes. Organizations should also consider implementing least privilege principles for users who have access to WebDAV clients, reducing the potential impact of successful exploitation attempts.