CVE-2015-3968 in UMG
Summary
by MITRE
The FTP service on Janitza UMG 508, 509, 511, 604, and 605 devices has a default password, which makes it easier for remote attackers to read or write to files via a session on TCP port 21.
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Analysis
by VulDB Data Team • 06/25/2022
The vulnerability identified as CVE-2015-3968 affects multiple models of Janitza UMG series power measurement devices including the UMG 508, 509, 511, 604, and 605 models. These industrial devices are commonly deployed in energy monitoring and management systems where they collect critical power consumption data and control various electrical parameters. The vulnerability stems from the FTP service configuration which utilizes a hardcoded default password, creating a significant security weakness that can be exploited by unauthorized parties. This flaw represents a classic case of poor credential management and weak authentication mechanisms in industrial control systems. The default password configuration allows any remote attacker with knowledge of the device model to establish an FTP session on the standard TCP port 21, thereby gaining unauthorized access to the device's file system. This vulnerability is particularly concerning in industrial environments where such devices often operate in network segments with limited security monitoring and may be exposed to external networks without proper network segmentation. The presence of default credentials in industrial equipment falls under CWE-798, which specifically addresses the use of hard-coded credentials that should never be present in production systems. The operational impact of this vulnerability extends beyond simple unauthorized access as it enables attackers to read sensitive configuration files, modify device settings, and potentially disrupt power monitoring operations that are critical for industrial processes and energy management.
The technical exploitation of this vulnerability requires minimal effort since attackers only need to know the device model to determine the default FTP credentials. Once connected via FTP on port 21, an attacker can perform various malicious activities including uploading malicious firmware, modifying configuration parameters, or extracting sensitive operational data that could reveal critical infrastructure information. This attack vector aligns with ATT&CK technique T1105 which describes the use of remote services to gain access to systems. The vulnerability's severity is amplified by the fact that these industrial devices typically operate continuously and may be located in physically accessible areas where network access can be easily obtained. The default password scenario creates a persistent security risk that remains active until the device administrator explicitly changes the credentials, which often does not occur in large industrial deployments where device management is centralized or where security awareness is lacking. The vulnerability also demonstrates poor adherence to the principle of least privilege, as the FTP service provides full file system access without proper authentication mechanisms or access controls. Network administrators should note that this vulnerability can be detected through network scanning activities that identify open FTP ports with default credentials, making it particularly attractive to automated exploitation tools.
Mitigation strategies for CVE-2015-3968 must include immediate credential changes on all affected devices, as this represents the most direct and effective solution to prevent exploitation. Organizations should implement comprehensive device inventory management to identify all instances of these vulnerable Janitza devices within their network infrastructure and ensure that default passwords are changed to strong, unique credentials. Network segmentation should be implemented to isolate these devices from critical network segments, and access to TCP port 21 should be restricted through firewall rules to only trusted administrative systems. Regular security assessments should be conducted to identify similar vulnerabilities in other industrial equipment, as this vulnerability type is commonly found in industrial control systems and IoT devices. The implementation of network monitoring solutions that can detect unauthorized FTP access attempts and credential guessing activities provides additional layers of defense. Organizations should also consider disabling FTP services entirely if they are not required for operational purposes, as many industrial devices offer alternative secure management interfaces such as SSH or HTTPS. Compliance with industrial security standards including IEC 62443 and NIST SP 800-82 should be enforced to ensure proper device configuration and security management practices are implemented across industrial networks. The vulnerability also highlights the importance of supply chain security and the need for manufacturers to implement secure-by-design principles that eliminate default credentials from production devices.