CVE-2017-16788 in Lantime
Summary
by MITRE
Directory traversal vulnerability in the "Upload Groupkey" functionality in the Web Configuration Utility in Meinberg LANTIME devices with firmware before 6.24.004 allows remote authenticated users with Admin-User access to write to arbitrary files and consequently gain root privileges by uploading a file, as demonstrated by storing a file in the cron.d directory.
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Analysis
by VulDB Data Team • 12/15/2019
The CVE-2017-16788 vulnerability represents a critical directory traversal flaw within the Meinberg LANTIME device family's web configuration utility. This vulnerability specifically targets the "Upload Groupkey" functionality, which is designed to handle cryptographic key management for network time synchronization services. The flaw exists in firmware versions prior to 6.24.004, affecting a significant portion of Meinberg LANTIME devices deployed in enterprise and industrial environments where precise time synchronization is critical for network operations and security orchestration.
The technical implementation of this vulnerability stems from inadequate input validation and path manipulation within the file upload handler. When authenticated administrators attempt to upload group keys through the web interface, the system fails to properly sanitize the file path specification, allowing attackers to manipulate the destination directory. This directory traversal capability enables an attacker to write malicious files to sensitive system locations, particularly the cron.d directory which contains scheduled tasks executed with elevated privileges. The vulnerability is classified as a CWE-22 Directory Traversal attack pattern, where insufficient validation of user-supplied input leads to unauthorized file system access and manipulation.
The operational impact of this vulnerability extends far beyond simple file manipulation, as it provides a direct path to privilege escalation and system compromise. An authenticated attacker with Admin-User credentials can leverage this vulnerability to establish persistent backdoors, modify system binaries, or inject malicious cron jobs that execute with root privileges. This represents a significant escalation from the initial authenticated access level to full system compromise, making it particularly dangerous in environments where time synchronization devices serve as critical infrastructure components. The vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as it enables both command execution and privilege elevation through system file manipulation.
Organizations utilizing Meinberg LANTIME devices should prioritize immediate firmware updates to version 6.24.004 or later, which addresses this directory traversal vulnerability through proper input validation and path sanitization. Additional mitigations include implementing network segmentation to limit access to the web configuration utility, enforcing strict access controls for administrative accounts, and monitoring for suspicious file upload activities in system logs. The vulnerability demonstrates the importance of secure file handling practices in embedded systems and highlights the critical need for regular firmware updates in industrial control systems where time synchronization plays a fundamental role in network security operations.