CVE-2003-0872 in OpenServer
Summary
by MITRE
Certain scripts in OpenServer before 5.0.6 allow local users to overwrite files and conduct other unauthorized activities via a symlink attack on temporary files.
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Analysis
by VulDB Data Team • 06/15/2018
The vulnerability identified as CVE-2003-0872 represents a critical security flaw within OpenServer versions prior to 5.0.6 that stems from improper handling of temporary files during script execution. This issue creates a race condition scenario where local users can exploit symbolic link attacks to manipulate the system's file operations. The vulnerability specifically affects scripts that generate temporary files, which are then processed by the system without adequate validation of the file system state. Attackers can create malicious symbolic links that point to sensitive system files or directories, effectively allowing them to overwrite critical files or gain unauthorized access to system resources.
The technical implementation of this vulnerability involves a classic race condition attack pattern where the timing window between file creation and file access provides an opportunity for exploitation. When scripts in OpenServer create temporary files, they often use predictable naming conventions and standard locations that attackers can anticipate. The flaw occurs because the system does not properly validate whether the temporary file path points to a legitimate file or has been manipulated through symbolic links. This weakness is particularly dangerous because it operates at the file system level and can be exploited by any local user with basic system access, making it a significant vector for privilege escalation attacks. The vulnerability aligns with CWE-367 which describes the improper handling of symbolic links in file operations, specifically addressing the race condition between file existence checks and actual file access.
The operational impact of CVE-2003-0872 extends beyond simple file overwrites to encompass broader system compromise possibilities. Local attackers can leverage this vulnerability to modify critical system files, potentially leading to complete system takeover or persistent backdoor access. The attack can be executed without requiring elevated privileges initially, making it particularly dangerous in multi-user environments where users might have legitimate access to script execution capabilities. This vulnerability directly impacts the integrity and confidentiality of system data, as attackers can manipulate not only temporary files but also potentially overwrite configuration files, log files, or even executable programs that are processed by the affected scripts. The attack vector also enables unauthorized modification of system logs, which can be used to cover tracks or manipulate audit trails, making detection and forensic analysis more difficult.
Mitigation strategies for this vulnerability require immediate implementation of proper file system validation mechanisms and system updates to OpenServer 5.0.6 or later versions where the issue has been resolved. Organizations should implement secure temporary file creation practices that avoid predictable naming conventions and ensure proper file permissions are enforced. The recommended approach includes using atomic file creation methods that prevent symbolic link manipulation, such as creating files with unique identifiers and immediately setting restrictive permissions. System administrators should also conduct thorough audits of all scripts that create temporary files to identify and remediate similar vulnerabilities across the environment. This vulnerability demonstrates the importance of following secure coding practices and adheres to ATT&CK technique T1059.007 which covers script execution through command-line interfaces, emphasizing the need for proper input validation and file system access controls in script-based applications. The fix typically involves implementing proper temporary file handling procedures that prevent attackers from creating or manipulating symbolic links in the temporary file creation path, thereby eliminating the race condition that enables the attack.