CVE-2018-16563 in EN100 Ethernet Module
Summary
by MITRE
A vulnerability has been identified in Firmware variant IEC 61850 for EN100 Ethernet module (All versions < V4.35), Firmware variant MODBUS TCP for EN100 Ethernet module (All versions), Firmware variant DNP3 TCP for EN100 Ethernet module (All versions), Firmware variant IEC104 for EN100 Ethernet module (All versions), Firmware variant Profinet IO for EN100 Ethernet module (All versions), SIPROTEC 5 relays with CPU variants CP300 and CP100 and the respective Ethernet communication modules (All versions < V7.82), SIPROTEC 5 relays with CPU variants CP200 and the respective Ethernet communication modules (All versions < V7.58). Specially crafted packets to port 102/tcp could cause a denial-of-service condition in the affected products. A manual restart is required to recover the EN100 module functionality of the affected devices. Successful exploitation requires an attacker with network access to send multiple packets to the affected products or modules. As a precondition the IEC 61850-MMS communication needs to be activated on the affected products or modules. No user interaction or privileges are required to exploit the vulnerability. The vulnerability could allow causing a Denial-of-Service condition of the network functionality of the device, compromising the availability of the system. At the time of advisory publication no public exploitation of this security vulnerability was known.
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Analysis
by VulDB Data Team • 08/03/2023
This vulnerability affects multiple industrial firmware variants including IEC 61850, MODBUS TCP, DNP3 TCP, IEC104, and Profinet IO protocols implemented on EN100 Ethernet modules and SIPROTEC 5 relays. The flaw exists in the handling of specially crafted packets sent to port 102/tcp which is commonly used for IEC 61850 MMS (Manufacturing Message Specification) communication. The vulnerability represents a classic buffer overflow or input validation issue that occurs when the firmware fails to properly process malformed network packets. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and can also be categorized as CWE-122 for heap-based buffer overflows when memory management is improperly handled. The attack vector requires only network access to the affected devices, making it particularly dangerous in industrial environments where physical security may be limited.
The technical implementation of this vulnerability demonstrates a failure in protocol parsing and input validation within the firmware's network stack. When the affected devices receive malformed packets on port 102/tcp, the firmware's processing routine does not adequately validate the packet structure or length, leading to a condition where the device's network functionality becomes unresponsive. This denial-of-service condition affects the availability of the entire communication module, requiring manual restart to restore normal operation. The prerequisite for exploitation is that IEC 61850-MMS communication must be activated, which is common in industrial automation systems where this protocol is used for communication between protection relays and control systems. This requirement means that the vulnerability is more likely to be exploited in operational environments where these communication protocols are actively used.
The operational impact of this vulnerability extends beyond simple service disruption, as it compromises the availability and reliability of critical industrial control systems. In power grid protection systems, for example, the SIPROTEC 5 relays with their respective Ethernet communication modules are often deployed in critical infrastructure where network availability is paramount for system reliability and safety. The need for manual restart after exploitation creates a significant operational challenge, as it may require on-site personnel to access potentially dangerous equipment locations. This vulnerability can be mapped to ATT&CK technique T1499.004, which covers network denial of service attacks, and T1566.001, representing spearphishing with social engineering. The attack does not require user interaction or elevated privileges, making it particularly dangerous as it can be exploited remotely by attackers with basic network access.
Mitigation strategies should focus on network segmentation and access control to prevent unauthorized access to affected devices. Implementing network access control lists to restrict access to port 102/tcp from trusted sources only can significantly reduce the attack surface. Regular firmware updates should be applied to versions that address this vulnerability, with particular attention to the specified minimum versions V4.35 for IEC 61850 firmware and V7.82 for SIPROTEC 5 relays with CP300/CP100 variants. Network monitoring should be implemented to detect unusual packet patterns on port 102/tcp that may indicate exploitation attempts. Additionally, industrial network security solutions such as firewalls and intrusion detection systems should be configured to monitor for malformed packets that could exploit this vulnerability. The vulnerability highlights the importance of secure coding practices in industrial firmware development and demonstrates the need for comprehensive vulnerability management programs in critical infrastructure environments. Organizations should also consider implementing network isolation for critical protection systems to minimize the potential impact of such vulnerabilities.