CVE-2017-6406 in NetBackup
Summary
by MITRE
An issue was discovered in Veritas NetBackup Before 7.7.2 and NetBackup Appliance Before 2.7.2. Arbitrary privileged command execution, using whitelist directory escape with "../" substrings, can occur.
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Analysis
by VulDB Data Team • 04/19/2017
The vulnerability identified as CVE-2017-6406 represents a critical privilege escalation flaw affecting Veritas NetBackup and NetBackup Appliance software versions prior to 7.7.2 and 2.7.2 respectively. This vulnerability stems from inadequate input validation and path traversal mechanisms within the software's command execution framework. The flaw allows attackers to bypass security controls by exploiting a whitelist directory escape technique that utilizes "../" substrings to navigate outside of intended directories. The vulnerability operates at the core of the software's file system access controls, where legitimate path validation mechanisms are circumvented through carefully crafted directory traversal sequences.
The technical implementation of this vulnerability leverages a classic path traversal attack vector where the "../" sequence is used to escape restricted directories and execute commands with elevated privileges. This weakness specifically affects the command execution subsystem of NetBackup software, where user-supplied input is not properly sanitized before being processed in file system operations. The vulnerability demonstrates a failure in proper input validation and access control enforcement, allowing attackers to manipulate the system's path resolution logic to gain unauthorized access to privileged system functions. This type of flaw is categorized under CWE-22, which specifically addresses path traversal vulnerabilities, and represents a direct violation of secure coding practices that require proper input sanitization and access control validation.
The operational impact of this vulnerability is severe and far-reaching within enterprise environments that utilize Veritas NetBackup solutions. Attackers who successfully exploit this vulnerability can execute arbitrary commands with root privileges, potentially leading to complete system compromise, data exfiltration, and persistence mechanisms. The ability to escape whitelist restrictions means that attackers can bypass multiple layers of security controls that are typically designed to prevent unauthorized access to critical system functions. This vulnerability particularly affects backup and recovery environments where NetBackup systems often have elevated privileges and access to sensitive organizational data. The attack surface is significant since NetBackup systems typically serve as central points for data protection and recovery, making them attractive targets for adversaries seeking to gain persistent access to enterprise networks.
Organizations affected by this vulnerability should immediately implement mitigations including upgrading to the patched versions of Veritas NetBackup and NetBackup Appliance software. The recommended approach involves applying the vendor-provided security patches that address the path traversal logic and strengthen input validation mechanisms. Additionally, network segmentation and access control measures should be enhanced to limit exposure of NetBackup systems to untrusted networks. Security monitoring should be implemented to detect suspicious directory traversal patterns and unauthorized command execution attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques such as T1059.001 for command and script execution, and T1068 for local privilege escalation. Organizations should also consider implementing principle of least privilege configurations and regular security assessments to identify similar vulnerabilities in their backup and recovery infrastructure. The remediation process should include comprehensive testing of the patched software to ensure that the vulnerability is fully resolved without introducing new operational issues in the backup environment.