CVE-2001-1378 in Fetchmail
Summary
by MITRE
fetchmailconf in fetchmail before 5.7.4 allows local users to overwrite files of other users via a symlink attack on temporary files.
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Analysis
by VulDB Data Team • 06/04/2018
The vulnerability described in CVE-2001-1378 affects the fetchmailconf utility within the fetchmail package version 5.7.4 and earlier. This represents a classic symlink attack scenario that exploits improper handling of temporary files during the execution of administrative configuration tools. The fetchmail package serves as an email retrieval utility that fetches mail from remote servers and delivers it locally, making it a critical component in many email infrastructure setups.
The technical flaw manifests in the fetchmailconf utility's inadequate management of temporary files during its operation. When the utility executes, it creates temporary files that are susceptible to symbolic link attacks. A local attacker who can influence the creation or location of these temporary files can establish symbolic links that point to sensitive system files or files belonging to other users. This vulnerability falls under the category of improper file handling and insecure temporary file creation, which are commonly classified as CWE-377 and CWE-378 within the CWE database. The attack vector specifically exploits the principle of least privilege by allowing unauthorized file access through manipulation of temporary file creation processes.
The operational impact of this vulnerability extends beyond simple file overwriting, as it enables privilege escalation and potential data compromise across user accounts on the same system. Local users who can execute fetchmailconf can leverage this flaw to overwrite files owned by other users, potentially gaining access to sensitive information or corrupting critical system files. This vulnerability particularly affects systems where multiple users share the same machine and where fetchmailconf is used for configuration management. The attack requires local access but can result in significant security implications, as it allows for unauthorized modification of system resources and user data. According to ATT&CK framework, this vulnerability maps to T1059.001 for command and script interpreter and T1548.002 for abuse of cloud compute infrastructure when considering the broader attack surface.
Mitigation strategies for CVE-2001-1378 focus primarily on updating to fetchmail version 5.7.4 or later, where the problematic temporary file handling has been corrected. Additionally, system administrators should implement proper file permissions and access controls to limit the ability of local users to manipulate temporary file creation processes. The fix typically involves using secure temporary file creation methods such as mkstemp or similar functions that guarantee unique file names and prevent symbolic link attacks. Organizations should also consider implementing privilege separation techniques and restricting access to administrative configuration tools to reduce the attack surface. System hardening measures including regular security audits and monitoring for unauthorized file modifications further strengthen defenses against this type of vulnerability. The remediation process should include comprehensive testing to ensure that the updated fetchmail configuration does not introduce compatibility issues while maintaining the security improvements.