CVE-2017-8023 in NetWorker
Summary
by MITRE
EMC NetWorker may potentially be vulnerable to an unauthenticated remote code execution vulnerability in the Networker Client execution service (nsrexecd) when oldauth authentication method is used. An unauthenticated remote attacker could send arbitrary commands via RPC service to be executed on the host system with the privileges of the nsrexecd service, which runs with administrative privileges.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 08/21/2023
The vulnerability identified as CVE-2017-8023 represents a critical remote code execution flaw within EMC NetWorker's Networker Client execution service, specifically affecting systems utilizing the oldauth authentication method. This vulnerability resides in the nsrexecd service component that operates with elevated administrative privileges, creating a severe security risk for organizations relying on EMC NetWorker for backup and recovery operations. The flaw enables attackers to execute arbitrary commands on affected systems without requiring authentication credentials, fundamentally compromising system integrity and potentially leading to complete system compromise.
Technical exploitation of this vulnerability leverages the RPC service interface of the nsrexecd component, which is designed to handle remote execution requests from client systems. When the oldauth authentication method is enabled, the service fails to properly validate incoming RPC requests, allowing unauthenticated attackers to inject and execute malicious commands directly on the target system. The nsrexecd service operates with administrative privileges, meaning that successful exploitation results in immediate elevation of attacker capabilities to system administrator level. This authentication bypass occurs at the service level rather than requiring legitimate user credentials, making the attack vector particularly dangerous as it can be exploited by anyone with network access to the affected RPC endpoints.
The operational impact of this vulnerability extends beyond simple remote code execution, as it fundamentally undermines the security model of EMC NetWorker implementations. Organizations using the oldauth method are exposed to potential data breaches, system compromise, and unauthorized access to backup systems that may contain sensitive organizational data. The vulnerability affects the core backup infrastructure, potentially allowing attackers to manipulate backup operations, access backup data, or even corrupt backup repositories. This risk is compounded by the fact that the nsrexecd service typically runs continuously and listens for incoming RPC connections, making it a persistent attack surface that remains accessible to unauthorized users. The vulnerability affects multiple versions of EMC NetWorker and can be exploited across various network environments where the service is exposed to untrusted networks.
Mitigation strategies for CVE-2017-8023 focus on disabling the vulnerable oldauth authentication method and implementing proper network segmentation to restrict access to the nsrexecd service ports. Organizations should immediately disable the oldauth authentication method and migrate to more secure authentication mechanisms such as the default auth method or TLS-based authentication. Network administrators should implement firewall rules to restrict access to the RPC ports used by nsrexecd, typically port 10000, to only trusted network segments. The vulnerability aligns with CWE-284 Access Control Issues and represents a classic privilege escalation scenario where insufficient authentication controls allow unauthorized users to execute code with elevated privileges. From an ATT&CK framework perspective, this vulnerability maps to T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation, demonstrating how initial access can quickly escalate to full system compromise. Organizations should also implement monitoring for unusual RPC activity and consider implementing intrusion detection systems to identify potential exploitation attempts against the vulnerable service.