CVE-2016-7489 in Virtual Machine Community Edition
Summary
by MITRE
Teradata Virtual Machine Community Edition v15.10's perl script /opt/teradata/gsctools/bin/t2a.pl creates files in /tmp in an insecure manner, this may lead to elevated code execution.
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Analysis
by VulDB Data Team • 06/04/2019
The vulnerability identified as CVE-2016-7489 affects Teradata Virtual Machine Community Edition version 15.10 and stems from insecure file creation practices within the perl script t2a.pl located at /opt/teradata/gsctools/bin/t2a.pl. This script operates within the context of a privileged environment and creates temporary files in the /tmp directory without proper security measures. The insecure temporary file creation pattern represents a well-documented security weakness that aligns with CWE-377, which addresses insecure temporary file handling in software applications. The flaw specifically manifests when the script generates files in the /tmp directory without implementing proper access controls or atomic creation mechanisms that would prevent malicious users from exploiting the temporary file race condition.
The technical exploitation of this vulnerability occurs through a classic race condition attack vector where an attacker can create a symbolic link or hard link to a file in the /tmp directory that the vulnerable script intends to create. This allows the attacker to manipulate the content of files that the script later processes, potentially leading to code execution with elevated privileges. The attack leverages the fact that the script does not implement proper file creation atomicity or temporary file permissions that would prevent unauthorized modification. This weakness directly maps to ATT&CK technique T1059.007, which covers scripting languages such as perl, and represents a privilege escalation opportunity within the system.
The operational impact of this vulnerability extends beyond simple code execution as it provides a potential pathway for attackers to gain unauthorized access to the Teradata virtual machine environment. Since the vulnerable script operates with elevated privileges due to its location within the Teradata tooling framework, successful exploitation could result in complete system compromise. The temporary file creation pattern is particularly dangerous because /tmp directories are often world-writable and accessible by unprivileged users, making the race condition attack surface quite broad. This vulnerability demonstrates poor security hygiene in file handling practices and represents a failure to follow secure coding guidelines that would prevent such insecure temporary file creation patterns.
Mitigation strategies for this vulnerability should focus on implementing proper secure file creation practices including the use of atomic file creation methods, proper file permissions, and ensuring that temporary files are created with restricted access controls. The recommended approach involves modifying the t2a.pl script to use secure temporary file creation functions that prevent race conditions, such as creating files with unique names and proper permissions before making them accessible. Organizations should also consider implementing proper file system permissions and monitoring for unauthorized modifications to critical system directories. The vulnerability highlights the importance of following secure coding practices as outlined in industry standards and demonstrates how seemingly minor implementation flaws can create significant security risks within enterprise software environments.