CVE-2008-4968 in lmbench
Summary
by MITRE
The (1) rccs and (2) STUFF scripts in lmbench 3.0-a7 allow local users to overwrite arbitrary files via a symlink attack on a /tmp/sdiff.##### temporary file.
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Analysis
by VulDB Data Team • 05/17/2025
The vulnerability identified as CVE-2008-4968 affects the lmbench 3.0-a7 benchmarking suite and specifically targets two scripts named rccs and STUFF that are susceptible to symlink attacks. This flaw represents a classic race condition vulnerability where local users can exploit the insecure handling of temporary files during script execution. The vulnerability occurs when these scripts create or access the temporary file located at /tmp/sdiff without proper security measures to prevent symbolic link manipulation. The attack vector exploits the predictable naming of temporary files and the lack of atomic file creation mechanisms that would prevent malicious users from substituting the intended temporary file with a symbolic link pointing to a target file of their choice.
This vulnerability falls under the category of insecure temporary file handling as classified by CWE-377, specifically CWE-378 which deals with the creation of temporary files with insecure permissions. The issue demonstrates poor security practices in file system operations where the scripts do not implement proper atomic file creation techniques or secure temporary file handling mechanisms. The attack requires local system access but provides a privilege escalation vector that allows attackers to overwrite arbitrary files on the system, potentially leading to persistent compromise or data corruption. The vulnerability is particularly concerning because it operates at the file system level and can be exploited by users who have minimal privileges but are able to execute the affected scripts.
The operational impact of this vulnerability extends beyond simple file overwriting as it can be leveraged in conjunction with other attack techniques to achieve more significant system compromise. An attacker could potentially overwrite critical system files, configuration files, or even binaries that are executed by the affected scripts or other system processes. The vulnerability also aligns with ATT&CK technique T1059.001 which involves executing malicious code through command-line interfaces, and T1074.001 which covers data staging through temporary files. The race condition aspect of this vulnerability makes it particularly dangerous because it can be exploited repeatedly and may be difficult to detect in normal system monitoring activities.
Mitigation strategies for this vulnerability should focus on implementing secure temporary file handling practices that prevent symlink attacks. The most effective approach involves using atomic file creation methods such as creating files with exclusive access permissions or using system calls that guarantee file creation without race conditions. The affected scripts should be modified to use secure temporary file creation functions that either create the file with appropriate permissions or verify that the file was created by the current process. Additionally, system administrators should implement proper file system permissions and consider using more secure temporary file locations that are less accessible to regular users. The vulnerability also highlights the importance of proper input validation and secure coding practices in system administration tools, as these benchmarks are often executed with elevated privileges and can serve as attack vectors for more sophisticated compromises.