CVE-2015-3971 in UMG
Summary
by MITRE
The debug interface on Janitza UMG 508, 509, 511, 604, and 605 devices does not require authentication, which allows remote attackers to read or write to files, or execute arbitrary JASIC code, via a session on TCP port 1239.
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Analysis
by VulDB Data Team • 02/23/2018
The vulnerability identified as CVE-2015-3971 affects Janitza UMG series power measurement devices including models 508, 509, 511, 604, and 605. These industrial devices are commonly deployed in energy management and monitoring systems where they collect and transmit critical operational data. The flaw resides in the device's debug interface implementation which fails to enforce proper authentication mechanisms, creating a significant security risk for industrial control systems. This vulnerability operates at the network level and specifically targets TCP port 1239 which serves as the designated interface for debugging operations within these devices.
The technical nature of this vulnerability stems from the absence of authentication requirements for the debug interface, making it accessible to any remote attacker who can establish a TCP connection to the designated port. This design flaw allows unauthorized parties to perform privileged operations including file read and write access, as well as execution of arbitrary JASIC code which is the scripting language used by these devices for configuration and automation tasks. The lack of authentication control represents a critical failure in the principle of least privilege and violates fundamental security practices for networked industrial equipment. This vulnerability directly maps to CWE-284 which describes improper access control and CWE-915 which addresses improper control of a resource through mechanism.
The operational impact of this vulnerability extends beyond simple unauthorized access as it provides attackers with complete control over the affected devices. Remote attackers can manipulate device configurations, access sensitive operational data, and potentially disrupt power monitoring functions that may be critical for grid stability and energy management. The ability to execute arbitrary JASIC code means that attackers can modify device behavior, install malicious code, or disable security features entirely. This vulnerability poses particular risk in industrial environments where these devices may be connected to critical infrastructure, as it could enable attackers to compromise entire power monitoring networks and potentially cause operational disruptions or data breaches.
Mitigation strategies for this vulnerability require immediate implementation of network segmentation and access controls to restrict access to TCP port 1239. Organizations should disable the debug interface when not actively required for maintenance operations and implement network firewalls to block external access to the affected port. Device administrators should also consider implementing network access control lists that restrict access to only trusted network segments. According to ATT&CK framework, this vulnerability aligns with techniques such as T1071.004 for application layer protocol usage and T1046 for network service scanning, while the exploitation would constitute T1059.007 for script execution. Regular security assessments and firmware updates should be implemented to address similar authentication flaws in industrial control systems and ensure compliance with industrial security standards such as IEC 62443 and NIST SP 800-82 for industrial control systems security.