CVE-2005-0205 in KDE
Summary
by MITRE
KPPP 2.1.2 in KDE 3.1.5 and earlier, when setuid root without certain wrappers, does not properly close a privileged file descriptor for a domain socket, which allows local users to read and write to /etc/hosts and /etc/resolv.conf and gain control over DNS name resolution by opening a number of file descriptors before executing kppp.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 03/10/2021
The vulnerability described in CVE-2005-0205 represents a critical privilege escalation flaw within the KPPP component of KDE 3.1.5 and earlier versions. This issue specifically affects the setuid root execution context where KPPP operates with elevated privileges to manage PPP connections. The flaw manifests when KPPP is executed without proper wrapper mechanisms that would normally sanitize the execution environment, creating a dangerous condition where privileged file descriptors remain open during the program's execution lifecycle. This vulnerability falls under the CWE-362 category of Concurrent Execution using Shared Resource with Improper Synchronization, as it involves improper handling of shared privileged resources during program execution.
The technical exploitation mechanism relies on the improper closure of a privileged file descriptor associated with a domain socket. When KPPP initializes without adequate security wrappers, it maintains access to a file descriptor that provides unrestricted access to critical system configuration files. Local attackers can exploit this by pre-opening multiple file descriptors before executing KPPP, effectively allowing them to leverage the open privileged descriptor to manipulate system network configuration files. This includes the ability to modify /etc/hosts and /etc/resolv.conf, which are fundamental components in DNS resolution and host name mapping. The vulnerability demonstrates poor resource management practices where the program fails to properly clean up privileged resources during its initialization phase, creating a persistent security exposure.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it provides attackers with complete control over DNS name resolution for the affected system. By modifying /etc/hosts, attackers can redirect network traffic to malicious destinations, while controlling /etc/resolv.conf allows them to manipulate DNS server configurations and potentially redirect all DNS queries through compromised servers. This creates a powerful attack vector for man-in-the-middle attacks, credential harvesting, and network reconnaissance activities. The vulnerability is particularly dangerous in multi-user environments where local access to a compromised system could lead to widespread network compromise. From an attacker's perspective, this represents a low-effort, high-impact exploit that requires minimal privileges to achieve significant system control, aligning with ATT&CK technique T1068 for local privilege escalation.
Mitigation strategies for this vulnerability require immediate system updates to patched versions of KDE that properly close privileged file descriptors during program initialization. Organizations should implement mandatory wrapper scripts that sanitize the execution environment before allowing setuid programs to run, ensuring that file descriptors are properly closed before privilege escalation occurs. System administrators should also monitor for unauthorized local access to systems running vulnerable KDE versions and implement proper file descriptor management practices. The fix typically involves modifying the program initialization sequence to explicitly close all unnecessary file descriptors before dropping privileges, which aligns with security best practices outlined in the principle of least privilege and proper resource cleanup. Additionally, regular security audits should verify that setuid programs properly manage their file descriptor lifecycle to prevent similar issues from emerging in other system components.