CVE-2018-20396 in MNG2120J
Summary
by MITRE
NET&SYS MNG2120J 5.76.1006c and MNG6300 5.83.6305jrc2 devices allow remote attackers to discover credentials via iso.3.6.1.4.1.4491.2.4.1.1.6.1.1.0 and iso.3.6.1.4.1.4491.2.4.1.1.6.1.2.0 SNMP requests.
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Analysis
by VulDB Data Team • 04/23/2020
The vulnerability identified as CVE-2018-20396 affects NET&SYS MNG2120J version 5.76.1006c and MNG6300 version 5.83.6305jrc2 network management devices, representing a significant security flaw in industrial network infrastructure. This issue stems from improper handling of Simple Network Management Protocol (SNMP) requests within the device firmware, specifically exposing credential information through well-defined SNMP object identifiers. The affected devices operate within industrial control systems and network management environments where such vulnerabilities can have cascading effects on operational technology infrastructure. The vulnerability allows remote attackers to extract sensitive authentication information without requiring any authentication credentials, making it particularly dangerous in environments where network segmentation may be inadequate.
The technical flaw manifests through the exposure of SNMP MIB (Management Information Base) values that contain credential information. Specifically, the vulnerable devices respond to SNMP requests targeting iso.3.6.1.4.1.4491.2.4.1.1.6.1.1.0 and iso.3.6.1.4.1.4491.2.4.1.1.6.1.2.0 object identifiers, which correspond to sensitive configuration data including usernames and potentially passwords or other authentication tokens. This represents a classic information disclosure vulnerability where the device fails to properly validate or restrict access to sensitive MIB values that should remain protected within the device's internal configuration. The vulnerability is classified under CWE-200 as "Information Exposure" and aligns with ATT&CK technique T1082 "System Information Discovery" when attackers use such information to map network assets and identify potential attack vectors.
The operational impact of this vulnerability extends beyond simple credential exposure, as it provides attackers with foundational information for further exploitation within industrial networks. Once credentials are obtained, attackers can potentially gain unauthorized access to device management interfaces, modify network configurations, or establish persistent access points within the operational technology environment. The vulnerability affects devices commonly used in industrial settings where network management and monitoring capabilities are critical for system operations. The remote nature of the attack means that adversaries can exploit this vulnerability from external network locations, significantly expanding the potential attack surface and reducing the effectiveness of traditional network perimeter defenses. This vulnerability directly impacts the CIA triad by compromising confidentiality of system credentials and potentially enabling integrity violations through unauthorized configuration changes.
Mitigation strategies for CVE-2018-20396 should focus on immediate network segmentation and access control measures. Organizations should implement strict SNMP access controls, ensuring that only authorized management stations can query sensitive MIB values. The recommended approach includes disabling SNMPv1 and SNMPv2c on affected devices, implementing SNMPv3 with strong authentication and encryption, and configuring firewall rules to restrict SNMP traffic to trusted management stations only. Network administrators should also conduct comprehensive vulnerability assessments to identify other potentially affected devices within their industrial control systems and operational technology environments. The vulnerability highlights the importance of secure configuration management practices and the need for regular firmware updates to address known security issues in industrial network equipment. Additionally, implementing network monitoring solutions that can detect unusual SNMP traffic patterns may help identify exploitation attempts and provide early warning capabilities for potential attacks targeting similar vulnerabilities in industrial control systems.