CVE-2001-0496 in KDELibs
Summary
by MITRE
kdesu in kdelibs package creates world readable temporary files containing authentication info, which can allow local users to gain privileges.
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Analysis
by VulDB Data Team • 04/26/2019
The vulnerability identified as CVE-2001-0496 resides within the kdesu component of the kdelibs package, which is part of the KDE desktop environment for linux systems. This flaw represents a critical security issue that exploits improper file permission handling during authentication processes. The kdesu utility is designed to allow users to execute commands with elevated privileges, typically requiring authentication through a graphical interface. When users authenticate through kdesu, the system creates temporary files to store authentication credentials and session information. These temporary files are created with overly permissive world-readable permissions, allowing any local user on the system to access the sensitive data contained within them.
The technical implementation of this vulnerability stems from the kdesu utility's failure to properly secure temporary files during the privilege escalation process. When authentication occurs, the system generates temporary files that contain authentication tokens, user credentials, or session data necessary for the privilege escalation to function. These files are created with default umask settings or explicit permission settings that grant read access to all users on the system. This design flaw directly violates security principles of least privilege and proper resource management, as the temporary files containing sensitive authentication information should only be accessible to the specific user and process that created them. The vulnerability is classified under CWE-732, which deals with Incorrect Permission Assignment for Critical Resources, and represents a classic case of insecure temporary file handling that has been documented in numerous security assessments over the years.
The operational impact of this vulnerability is significant for systems running affected versions of kdelibs. Local users who can access the system can exploit this weakness by simply reading the world-readable temporary files created by kdesu. Once these files are accessed, attackers can extract authentication information and potentially use it to escalate their privileges to root or other elevated user accounts. This creates a serious privilege escalation vector that undermines the security model of the entire system. The attack requires minimal skill and can be automated, making it particularly dangerous in multi-user environments where attackers may not have direct access to the system but can still monitor and exploit shared resources. The vulnerability effectively bypasses the intended authentication mechanisms of kdesu, rendering the privilege escalation process insecure and exploitable by any local user. This flaw has implications for compliance with security standards such as those outlined in the NIST Special Publication 800-53, which emphasizes the importance of proper access control and privilege management in secure system design.
Mitigation strategies for this vulnerability involve immediate patching of the kdelibs package to ensure that temporary files are created with appropriate permissions that restrict access to the owning user only. System administrators should verify that temporary files are created using secure umask settings or explicit permission controls that prevent world readability. The recommended approach includes implementing proper file permission management where temporary files are created with permissions set to 600 or similar restrictive settings. Additionally, organizations should conduct regular security audits to identify and remediate similar insecure temporary file handling practices across their systems. This vulnerability highlights the importance of proper file system security practices and the need for comprehensive security testing of privilege escalation mechanisms. The remediation process should also include monitoring for any unauthorized access to temporary files and implementing logging mechanisms to track access patterns that may indicate exploitation attempts. Security frameworks such as those defined in the MITRE ATT&CK matrix categorize this as a privilege escalation technique that can be leveraged by adversaries to gain elevated system access through insecure file handling practices.