CVE-2016-3989 in IMS-LANTIME
Summary
by MITRE
The NTP time-server interface on Meinberg IMS-LANTIME M3000, IMS-LANTIME M1000, IMS-LANTIME M500, LANTIME M900, LANTIME M600, LANTIME M400, LANTIME M300, LANTIME M200, LANTIME M100, SyncFire 1100, and LCES devices with firmware before 6.20.004 allows remote authenticated users to obtain root privileges for writing to unspecified scripts, and consequently obtain sensitive information or modify data, by leveraging access to the nobody account.
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Analysis
by VulDB Data Team • 07/08/2024
The vulnerability identified as CVE-2016-3989 affects a critical component of Meinberg IMS-LANTIME and LANTIME series time synchronization devices, specifically those running firmware versions prior to 6.20.004. These industrial time servers are widely deployed in network infrastructure environments where precise time synchronization is essential for maintaining system integrity and security. The affected devices operate with a Network Time Protocol (NTP) time-server interface that provides remote access capabilities, making them attractive targets for attackers seeking to compromise industrial control systems. The vulnerability resides in the privilege escalation mechanism within the NTP interface implementation, where authenticated remote users can exploit a flaw in the system's access control model to gain root privileges. This represents a significant security weakness in industrial network equipment, particularly in environments where these devices serve as time references for critical infrastructure components.
The technical flaw stems from improper privilege handling within the NTP time-server interface implementation, specifically related to how the system processes authentication requests from the nobody account. The vulnerability allows authenticated users to leverage their access to the nobody account to execute privileged operations that should be restricted to administrative users only. This privilege escalation occurs through unspecified script writing capabilities that are not properly protected from unauthorized access. The flaw essentially creates a backdoor path where legitimate authentication does not properly enforce privilege boundaries, enabling attackers to execute commands with root privileges. This type of vulnerability is classified under CWE-276, which deals with improper privilege management, and represents a classic case of insufficient access control that allows privilege escalation from a lower-privileged account to full administrative control. The NTP interface's design fails to properly validate the execution context of commands, creating opportunities for unauthorized privilege elevation.
The operational impact of this vulnerability is severe for organizations relying on these time synchronization devices, as it provides attackers with complete control over the affected systems. Once an attacker gains root privileges through this vulnerability, they can access sensitive system information, modify critical configuration data, and potentially disrupt network time synchronization services that may be fundamental to other network operations. The ability to write to unspecified scripts creates additional attack vectors where malicious code could be injected into the system, potentially leading to persistent backdoors or further compromise of network infrastructure. This vulnerability affects multiple models within the Meinberg product line, indicating a widespread issue that could impact numerous industrial installations simultaneously. The implications extend beyond simple privilege escalation, as these devices often serve as time references for critical network services, making them attractive targets for attackers seeking to disrupt or manipulate network operations across larger infrastructures. This vulnerability aligns with ATT&CK technique T1068, which covers privilege escalation through local exploitation, and demonstrates how industrial control systems can be compromised through network-based attacks that leverage legitimate access mechanisms.
The recommended mitigation strategy involves immediate firmware updates to version 6.20.004 or later, which addresses the privilege escalation vulnerability in the NTP time-server interface. Organizations should also implement network segmentation to restrict access to these time servers, limiting the attack surface by ensuring only authorized network segments can reach the devices. Additional protective measures include implementing strong authentication controls, monitoring NTP interface access logs for suspicious activity, and conducting regular vulnerability assessments of industrial control systems. Network administrators should also consider disabling unnecessary NTP services when not required and implementing network access controls that restrict the nobody account's ability to perform privileged operations. The vulnerability highlights the importance of maintaining up-to-date industrial control system firmware and demonstrates the critical need for proper access control implementation in network infrastructure devices that serve as time synchronization references for critical network operations.