CVE-2016-0911 in Data Domain OS
Summary
by MITRE
EMC Data Domain OS 5.4 through 5.7 before 5.7.2.0 has a default no_root_squash option for NFS exports, which makes it easier for remote attackers to obtain filesystem access by leveraging client root privileges.
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Analysis
by VulDB Data Team • 08/24/2022
The vulnerability identified as CVE-2016-0911 affects EMC Data Domain Operating System versions 5.4 through 5.7 before 5.7.2.0, representing a critical security flaw in network file sharing configurations. This issue stems from the default configuration of NFS (Network File System) exports that includes the no_root_squash option, a configuration that fundamentally compromises the security model of the system. The vulnerability falls under CWE-276, which specifically addresses improper privilege management, and aligns with ATT&CK technique T1077 for hijacking and T1046 for network service scanning. The default no_root_squash setting allows clients to access the filesystem with root privileges, effectively bypassing the normal access controls that should prevent unauthorized root-level access to system resources.
The technical flaw exploits a fundamental misconfiguration in the NFS export settings where the system defaults to allowing root users from client machines to retain their root privileges when accessing shared filesystems. This configuration creates a privilege escalation pathway where remote attackers can leverage the root privileges of client systems to gain full administrative access to the Data Domain system's filesystem. The vulnerability is particularly dangerous because it eliminates the normal security boundaries that separate client and server privileges, allowing attackers to perform operations that should be restricted to authorized administrators only. This misconfiguration essentially provides a backdoor for attackers to execute arbitrary commands with root privileges on the target system.
The operational impact of this vulnerability is severe and far-reaching, as it allows attackers to obtain complete control over the affected Data Domain systems without requiring additional authentication mechanisms or exploit chains. Remote attackers can leverage this vulnerability to access sensitive data, modify system configurations, install malicious software, and potentially use the compromised system as a pivot point to attack other systems within the network. The vulnerability affects organizations that rely on Data Domain systems for backup and storage operations, potentially exposing critical business data to unauthorized access. This flaw particularly impacts enterprise environments where Data Domain systems serve as primary storage solutions for corporate data, making it a high-value target for cybercriminals seeking to access sensitive information.
Organizations should immediately implement mitigations that include disabling the no_root_squash option for NFS exports and configuring proper access controls that restrict root privileges for remote clients. The recommended approach involves modifying the NFS export configuration to use the root_squash option, which maps root users from client machines to an unprivileged user account on the server. Security teams should also implement network segmentation to limit access to Data Domain systems, conduct regular vulnerability assessments, and ensure that systems are updated to version 5.7.2.0 or later where this vulnerability has been addressed. Additionally, organizations should monitor NFS traffic for suspicious access patterns and implement proper network access controls to prevent unauthorized access to these critical storage systems. The mitigation strategy should align with security frameworks such as NIST SP 800-53 and ISO 27001 to ensure comprehensive protection against similar vulnerabilities in the future.