CVE-2016-0917 in VNXe
Summary
by MITRE
The SMB service in EMC VNXe, VNX1 File OE before 7.1.80.3, and VNX2 File OE before 8.1.9.155 does not prevent duplicate NTLM challenge-response nonces, which makes it easier for remote attackers to execute arbitrary code, or read or write to files, via a series of authentication requests, a related issue to CVE-2010-0231.
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Analysis
by VulDB Data Team • 09/19/2022
The vulnerability identified as CVE-2016-0917 affects the Server Message Block service implementation within EMC VNXe and VNX1 File Operating Environments, specifically versions prior to 7.1.80.3 and VNX2 File OE prior to 8.1.9.155. This flaw represents a critical weakness in the authentication mechanism that governs file access and system operations through SMB protocols. The vulnerability stems from the service's inability to properly validate and reject duplicate NTLM challenge-response nonces, creating a pathway for malicious actors to exploit the authentication flow. This issue is particularly concerning as it directly impacts the security foundation of enterprise storage systems, where unauthorized access could lead to data compromise, system infiltration, or privilege escalation.
The technical flaw manifests in the SMB service's handling of NTLM authentication exchanges where the system fails to enforce proper nonce uniqueness validation. When multiple authentication requests are made, the service should reject duplicate nonces to prevent replay attacks and ensure that each authentication attempt is properly validated. However, in affected EMC systems, the service allows these duplicate nonces to be accepted, which creates opportunities for attackers to capture valid authentication responses and reuse them in subsequent authentication attempts. This behavior effectively weakens the authentication security model and enables attackers to potentially bypass authentication mechanisms entirely, gaining unauthorized access to file systems and network resources.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to execute arbitrary code on affected systems and perform read or write operations on files without proper authorization. Attackers can leverage this weakness to establish persistent access to storage environments, potentially leading to data exfiltration, system compromise, or disruption of business operations. The vulnerability's relationship to CVE-2010-0231 indicates a pattern of similar authentication weaknesses in SMB implementations, suggesting that organizations with multiple affected systems may face cascading security risks. This vulnerability particularly affects enterprise storage environments where VNXe and VNX1 systems are deployed, making it a significant concern for organizations relying on EMC storage solutions for critical data infrastructure.
Organizations should implement immediate mitigations including applying the vendor-provided patches and updates that address the nonce validation issue in the SMB service implementation. Network segmentation and access control measures should be strengthened to limit exposure of affected systems to untrusted networks. The vulnerability aligns with CWE-310 and CWE-312 categories related to cryptographic issues and weakness in authentication mechanisms. From an ATT&CK framework perspective, this vulnerability maps to techniques involving credential access and privilege escalation, specifically T1075 (Pass the Hash) and T1566 (Phishing for Information) where attackers could exploit the authentication weakness to gain unauthorized system access. Regular monitoring of authentication logs for unusual nonce patterns and implementing proper intrusion detection systems can help identify potential exploitation attempts. The remediation process should include comprehensive testing of patched systems to ensure that the nonce validation mechanisms function correctly and that no regression issues have been introduced in the updated software versions.