CVE-2017-4979 in Isilon OneFS
Summary
by MITRE
EMC Isilon OneFS 8.0.1.0, OneFS 8.0.0.0 - 8.0.0.2, OneFS 7.2.1.0 - 7.2.1.3, and OneFS 7.2.0.x is affected by an NFS export vulnerability. Under certain conditions, after upgrading a cluster from OneFS 7.1.1.x or earlier, users may have unexpected levels of access to some NFS exports.
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Analysis
by VulDB Data Team • 09/30/2020
The vulnerability identified as CVE-2017-4979 affects EMC Isilon OneFS storage systems across multiple version ranges including 8.0.1.0, 8.0.0.0 through 8.0.0.2, 7.2.1.0 through 7.2.1.3, and 7.2.0.x. This issue represents a significant access control flaw within the Network File System (NFS) export functionality that could potentially allow unauthorized users to gain elevated privileges or access to data they should not be permitted to access. The vulnerability specifically manifests during or immediately following cluster upgrades from older OneFS versions, particularly those based on 7.1.1.x or earlier releases, creating a window of opportunity for privilege escalation or unauthorized data access.
The technical root cause of this vulnerability stems from improper handling of NFS export permissions during the upgrade process from legacy OneFS versions. When clusters are upgraded from versions 7.1.1.x or earlier, the system fails to properly validate or reset the access control lists associated with NFS exports, leading to a situation where users may retain or gain unexpected access levels to previously restricted file systems. This flaw operates at the intersection of configuration management and access control enforcement, where the upgrade procedure does not adequately sanitize or re-evaluate existing export permissions. The vulnerability is particularly concerning because it affects the fundamental security model of the storage system, where NFS export permissions are critical for maintaining data isolation and access control boundaries.
The operational impact of CVE-2017-4979 extends beyond simple unauthorized access scenarios, potentially enabling attackers to escalate privileges or compromise data integrity within the storage environment. Organizations utilizing affected EMC Isilon systems may find that after upgrading their infrastructure, certain users or groups can access data that should be restricted to specific authorized personnel, potentially leading to data leakage, unauthorized modifications, or complete compromise of sensitive information stored within the cluster. The vulnerability affects the core file sharing functionality of the system, making it particularly dangerous in enterprise environments where data security and access control are paramount. Attackers could exploit this weakness to gain access to production data, backup systems, or other sensitive storage resources that should be protected from general access.
This vulnerability aligns with CWE-284, which describes improper access control issues, and represents a specific implementation flaw in how the system handles permission inheritance during upgrade operations. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1078 which covers valid accounts and privilege escalation, as the issue allows for unexpected access to resources that should remain restricted. Organizations should implement immediate mitigation strategies including thorough access control reviews, verification of NFS export configurations post-upgrade, and implementation of network segmentation to limit potential exploitation. The recommended remediation involves applying the appropriate EMC patch or upgrade to the OneFS system to ensure proper permission handling during upgrade operations, along with comprehensive testing of access controls to validate that the vulnerability has been resolved. Additionally, security teams should conduct regular audits of NFS export configurations and maintain strict change management procedures for storage system upgrades to prevent similar issues from occurring in the future.