CVE-2014-9201 in M-6200 Digital Voltage Regulator Control
Summary
by MITRE
Beckwith Electric M-6200 Digital Voltage Regulator Control with firmware before D-0198V04.07.00, M-6200A Digital Voltage Regulator Control with firmware before D-0228V02.01.07, M-2001D Digital Tapchanger Control with firmware before D-0214V01.10.04, M-6283A Three Phase Digital Capacitor Bank Control with firmware before D-0346V03.00.02, M-6280A Digital Capacitor Bank Control with firmware before D-0254V03.05.05, and M-6280 Digital Capacitor Bank Control do not properly generate TCP initial sequence number (ISN) values, which makes it easier for remote attackers to spoof TCP sessions by predicting an ISN value.
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Analysis
by VulDB Data Team • 04/04/2019
The vulnerability identified as CVE-2014-9201 affects several Beckwith Electric digital voltage and capacitor bank control devices including the M-6200 series, M-2001D, M-6283A, M-6280A, and M-6280 models. These industrial control systems operate in critical infrastructure environments where network connectivity is essential for remote monitoring and control operations. The flaw resides in the TCP stack implementation of these devices' firmware, specifically in how they generate initial sequence numbers for TCP connections. This weakness represents a fundamental security issue that undermines the integrity of network communications between control systems and their operators. The vulnerability impacts devices running firmware versions prior to specific thresholds including D-0198V04.07.00 for M-6200, D-0228V02.01.07 for M-6200A, D-0214V01.10.04 for M-2001D, D-0346V03.00.02 for M-6283A, and D-0254V03.05.05 for M-6280A. The improper generation of TCP initial sequence numbers creates a predictable pattern that adversaries can exploit to conduct successful TCP session hijacking attacks. According to the CWE (Common Weakness Enumeration) framework, this vulnerability maps to CWE-310, which specifically addresses cryptographic weakness in sequence number generation, making it particularly dangerous in industrial control environments where network security is paramount.
The technical flaw stems from the use of insufficiently random or predictable algorithms for generating TCP initial sequence numbers. In standard TCP implementations, sequence numbers must be unpredictable to prevent attackers from guessing valid sequence numbers and injecting malicious packets into established connections. When devices generate predictable sequence numbers, they create an opening for attackers to perform TCP sequence number prediction attacks, which fall under the ATT&CK technique T1071.004 for application layer protocol: DNS. The vulnerability allows remote attackers to establish fraudulent TCP sessions by predicting the sequence numbers that the vulnerable devices will use, effectively enabling session hijacking without requiring authentication. This weakness is particularly concerning in industrial environments where these devices control critical electrical infrastructure, as successful exploitation could lead to unauthorized access to control systems, potentially resulting in operational disruptions or safety hazards. The predictability of sequence numbers compromises the confidentiality, integrity, and availability of communications between control systems and their management interfaces.
The operational impact of this vulnerability extends beyond simple network security concerns to encompass potential safety and operational risks in industrial environments. When attackers can predict TCP sequence numbers, they gain the ability to inject malicious commands into control systems, potentially altering voltage levels, capacitor bank operations, or other critical electrical parameters. This capability represents a significant risk to industrial control systems and can lead to equipment damage, power quality issues, or even safety hazards for personnel working in proximity to these systems. The vulnerability affects devices that are typically deployed in utility substations, manufacturing facilities, and other industrial environments where continuous operation is critical. These devices often communicate over untrusted networks or through remote access connections, making them attractive targets for attackers seeking to compromise industrial control infrastructure. The risk is compounded by the fact that many of these devices operate in environments where network segmentation may be limited, and where traditional network security controls may not be sufficient to protect against such low-level protocol-level attacks.
Mitigation strategies for this vulnerability require a multi-layered approach combining immediate firmware updates with network security measures. The primary recommendation is to update all affected devices to the latest firmware versions that address the TCP sequence number generation issue, as provided by Beckwith Electric. Network segmentation should be implemented to isolate these control systems from general network traffic, reducing the attack surface available to potential adversaries. Implementing TCP sequence number randomization at the network level or through network security appliances can provide additional protection against prediction-based attacks. Organizations should also consider deploying intrusion detection systems specifically configured to monitor for TCP sequence number anomalies and other indicators of potential exploitation attempts. The implementation of network access control lists and firewalls can help limit access to these devices to authorized personnel only. Regular vulnerability assessments should be conducted to identify other potentially vulnerable industrial control systems within the network infrastructure, as similar vulnerabilities may exist in other components of the industrial control environment. This vulnerability highlights the importance of applying security patches promptly and maintaining awareness of industrial control system security issues, as outlined in various cybersecurity frameworks including NIST SP 800-82 and IEC 62443 standards for industrial automation and control systems security.