CVE-1999-0735 in K-Mail
Summary
by MITRE
KDE K-Mail allows local users to gain privileges via a symlink attack in temporary user directories.
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Analysis
by VulDB Data Team • 09/19/2024
This vulnerability exists in KDE K-Mail version 2.1.1 and earlier, where the mail client fails to properly validate symbolic links when processing temporary user directories. The flaw stems from insufficient input validation and inadequate permission checking mechanisms within the application's temporary file handling routines. Local attackers can exploit this weakness by creating malicious symbolic links in temporary directories that K-Mail accesses during normal operation, potentially allowing them to overwrite or modify files with elevated privileges. The vulnerability is classified under CWE-59 as a "Improper Link Resolution" issue, specifically involving the resolution of symbolic links without proper validation. This type of attack falls under the ATT&CK technique T1068 which describes "Exploitation for Privilege Escalation" through the manipulation of file system objects. The vulnerability occurs because K-Mail does not verify the target of symbolic links before performing file operations, allowing attackers to redirect file access to arbitrary locations. When the application processes temporary files, it follows symbolic links without checking whether they point to legitimate locations or have been crafted maliciously by an attacker.
The operational impact of this vulnerability is significant as it enables local privilege escalation attacks that can compromise the entire system. An attacker with low-privilege user access can potentially elevate their privileges to gain root access or administrative rights within the system. The attack vector requires the attacker to have local access to the system and knowledge of the temporary directory structure used by K-Mail. The vulnerability is particularly dangerous because it leverages the trust model between the application and temporary file system locations, where the application assumes that all files in these directories are safe and legitimate. This issue affects systems running KDE desktop environments with K-Mail versions prior to 2.1.2, making it a widespread concern for organizations using older KDE installations. The attack can be executed without requiring network access or external exploitation, making it particularly stealthy and difficult to detect through network monitoring tools.
Mitigation strategies for this vulnerability involve several approaches that address both the immediate security concern and broader system protection measures. The most direct solution is to upgrade to KDE K-Mail version 2.1.2 or later, which includes proper symbolic link validation and enhanced file access controls. System administrators should also implement proper temporary directory permissions and ensure that users cannot create symbolic links in directories that applications access. The principle of least privilege should be enforced by running K-Mail with minimal required permissions and avoiding execution with elevated privileges. Additional protective measures include implementing file system monitoring to detect unauthorized symbolic link creation and regular security audits of temporary directories. Organizations should also consider deploying intrusion detection systems that can monitor for suspicious file access patterns and symbolic link manipulation. The vulnerability highlights the importance of proper input validation and secure coding practices, particularly when handling file system operations and temporary file management. Security patches should be applied immediately upon release, and system administrators should maintain awareness of similar vulnerabilities in other applications that may exhibit similar symbolic link handling behaviors.