CVE-2008-4974 in netmrg
Summary
by MITRE
rrdedit in netmrg 0.20 allows local users to overwrite arbitrary files via a symlink attack on (1) /tmp/*.xml and (2) /tmp/*.backup temporary files.
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Analysis
by VulDB Data Team • 10/14/2018
The vulnerability identified as CVE-2008-4974 affects the rrdedit component within netmrg version 0.20, presenting a significant security risk through improper temporary file handling that enables local privilege escalation through symbolic link attacks. This flaw specifically targets the temporary file creation process where the application generates files with predictable naming patterns in the /tmp directory, creating opportunities for malicious users to manipulate the system's file operations.
The technical implementation of this vulnerability stems from the application's failure to properly validate or secure temporary file creation processes. When rrdedit processes user input or configuration data, it creates temporary files using fixed naming conventions such as /tmp/.xml and /tmp/.backup, which are susceptible to race conditions and symlink attacks. An attacker with local access can create symbolic links in the /tmp directory that point to critical system files, thereby causing the vulnerable application to write data to unintended locations when it attempts to create its temporary files. This type of vulnerability falls under the category of insecure temporary file handling as defined by CWE-377, specifically CWE-378 which addresses the creation of temporary files with insecure permissions and predictable names.
The operational impact of this vulnerability extends beyond simple file overwrites, as it enables attackers to potentially modify critical system files, configuration data, or even executable components that may be processed by the application or system services. Local users who can execute the rrdedit utility can leverage this weakness to gain elevated privileges or cause denial of service conditions by overwriting files in sensitive system locations. The attack vector requires local system access and the ability to create symbolic links in the /tmp directory, making it particularly concerning in multi-user environments where users may have limited privileges but can still execute the vulnerable application.
This vulnerability demonstrates the importance of proper file system security practices and follows patterns commonly associated with the attack technique T1548.001 in the MITRE ATT&CK framework, which covers privilege escalation through hijacking of system services or applications. The flaw represents a classic example of how predictable temporary file names and insufficient permission checks can create security weaknesses that allow local users to manipulate system state. Organizations should consider implementing additional security controls such as secure temporary file creation methods, proper file permission management, and regular security audits of system applications to prevent similar vulnerabilities from being exploited.
Mitigation strategies for this vulnerability include immediate patching of the netmrg application to version 0.21 or later, which addresses the temporary file handling issues through secure file creation mechanisms and proper validation of temporary file locations. System administrators should also implement proper file system permissions, ensuring that temporary directories have restricted write permissions and that symbolic link creation is properly controlled. Additional defensive measures include monitoring for unauthorized symbolic link creation in temporary directories, implementing file integrity monitoring solutions, and conducting regular security assessments to identify similar vulnerabilities in other system components. The vulnerability highlights the critical need for secure coding practices, particularly around temporary file handling, as specified in various security standards and best practices for application development and system administration.