CVE-2017-6404 in NetBackup
Summary
by MITRE
An issue was discovered in Veritas NetBackup Before 7.7 and NetBackup Appliance Before 2.7. There are world-writable log files, allowing destruction or spoofing of log data.
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Analysis
by VulDB Data Team • 09/02/2020
The vulnerability identified as CVE-2017-6404 represents a critical security flaw in Veritas NetBackup and NetBackup Appliance products that persisted across multiple versions prior to 7.7 and 2.7 respectively. This issue stems from improper file permissions that grant universal write access to specific log files within the system architecture. The flaw creates a significant attack surface where unauthorized users or malicious actors can manipulate system logging mechanisms to corrupt or fabricate audit trails that are essential for security monitoring and compliance verification. The root cause of this vulnerability aligns with CWE-732, which specifically addresses inadequate permissions for critical security resources, making it a prime target for privilege escalation and data integrity compromise attacks.
The technical exploitation of this vulnerability occurs through the manipulation of world-writable log files that are typically used for system monitoring, security event tracking, and audit purposes. Attackers can leverage these permissions to either destroy existing log entries, making it difficult to trace malicious activities, or to inject false log data that could mislead security personnel and automated monitoring systems. This dual capability significantly undermines the integrity of the logging infrastructure and compromises the organization's ability to maintain accurate security event records. The vulnerability's impact extends beyond simple data corruption as it directly affects the reliability of security information and event management systems that depend on trustworthy log data for threat detection and forensic analysis.
From an operational standpoint, the implications of CVE-2017-6404 are severe and multifaceted. Organizations relying on Veritas NetBackup systems face potential security breaches where attackers can hide their activities by modifying or deleting relevant log entries. This capability directly conflicts with the principles of non-repudiation and auditability that are fundamental to information security frameworks. The vulnerability creates opportunities for attackers to establish persistence within systems while simultaneously covering their tracks, making detection and incident response significantly more challenging. Additionally, the compromised logging infrastructure can lead to regulatory compliance issues, particularly in environments governed by standards such as pci dss, hipaa, or soc 2, where maintaining accurate audit trails is mandatory for operational continuity and legal compliance.
The attack surface for this vulnerability can be leveraged through various methods including local privilege escalation attacks, where attackers with basic system access can exploit the world-writable permissions to gain deeper system control. The flaw also aligns with several tactics described in the mitre att&ck framework, particularly those related to privilege escalation and defense evasion. Security professionals should consider implementing comprehensive monitoring of log file modifications and establishing automated alerting mechanisms to detect unauthorized changes to critical system logs. Organizations should also conduct immediate remediation by updating to versions 7.7 for NetBackup and 2.7 for NetBackup Appliance, while implementing proper file permission controls to ensure that log files maintain appropriate access restrictions. The vulnerability serves as a reminder of the critical importance of maintaining proper file system permissions and the necessity of regular security assessments to identify and remediate similar permission-related flaws that could compromise system integrity and security monitoring capabilities.