CVE-2002-2382 in CVSup
Summary
by MITRE
cvsupd.sh in CVSup 1.2 allows local users to overwrite arbitrary files and gain privileges via a symlink attack on /var/tmp/cvsupd.out.
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Analysis
by VulDB Data Team • 07/14/2024
The vulnerability identified as CVE-2002-2382 affects CVSup version 1.2, a tool used for distributing and synchronizing software packages across networks. This security flaw resides in the cvsupd.sh script which is part of the CVSup distribution system. The vulnerability represents a classic symlink attack scenario that exploits insecure temporary file handling practices. The issue occurs when the script creates temporary files in the /var/tmp directory without proper validation of symbolic link references, creating a window of opportunity for malicious local users to manipulate the file system.
The technical implementation of this vulnerability stems from the script's failure to properly secure temporary file creation processes. When cvsupd.sh executes, it generates temporary files in /var/tmp/cvsupd.out without verifying whether this path is a symbolic link to another location. This insecure practice allows a local attacker to establish a symbolic link at the expected temporary file location before the script creates its actual file, thereby redirecting the script's write operations to a target file of the attacker's choosing. This type of vulnerability is categorized under CWE-353, which addresses the weakness of "Check for Weak Cryptographic Hash or Encryption" but more accurately maps to CWE-377, "Insecure Temporary File" or CWE-367, "Path Traversal" depending on the specific implementation details.
The operational impact of this vulnerability is significant as it enables local privilege escalation attacks. An attacker who can execute code on the target system can leverage this weakness to overwrite critical system files, configuration files, or even setuid binaries with malicious content. The privilege escalation potential arises because the script likely runs with elevated privileges during its execution, allowing the attacker to modify files that would normally require administrative access. This scenario directly aligns with ATT&CK technique T1068, "Local Privilege Escalation," and specifically demonstrates how insecure temporary file handling can be exploited to gain unauthorized access to system resources. The vulnerability affects systems where CVSup is installed and running with elevated privileges, making it particularly dangerous in enterprise environments where such tools are commonly deployed for software distribution.
Mitigation strategies for this vulnerability require immediate remediation through patching the affected CVSup version or implementing proper file system access controls. Organizations should ensure that all temporary file operations use secure methods such as creating files with exclusive access permissions or using proper temporary file APIs that prevent symbolic link attacks. The recommended approach involves modifying the script to verify that temporary files are not symbolic links and to create temporary files using secure umask settings. Additionally, system administrators should implement proper file system permissions and regularly audit the /var/tmp directory for unauthorized symbolic links. This vulnerability highlights the importance of following secure coding practices and adheres to the principle of least privilege, where temporary file creation should never be vulnerable to symlink manipulation attacks. System hardening measures including regular security audits and implementing mandatory access controls can help prevent exploitation of similar weaknesses in other software components.