CVE-2018-20397 in CBC383Z
Summary
by MITRE
mplus CBC383Z CBC383Z_mplus_MDr026 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-2018-20397 affects mplus CBC383Z CBC383Z_mplus_MDr026 devices, representing a critical security flaw in networked industrial control systems. This issue manifests through the Simple Network Management Protocol implementation within these devices, specifically exposing sensitive credential information through managed objects accessible via standard SNMP queries. The vulnerability stems from improper access control mechanisms within the device's SNMP agent implementation, allowing unauthorized remote attackers to extract authentication credentials without requiring valid session tokens or prior authorization.
The technical exploitation occurs through specific SNMP object identifiers that correspond to credential storage locations within the device's management information base. The affected OIDs 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 represent the credential storage areas where usernames and passwords are maintained in a manner that violates standard security practices. These object identifiers are part of the mplus vendor-specific MIB structure and expose plaintext authentication information that should be protected from unauthorized access. This flaw directly relates to CWE-200, which describes the exposure of sensitive information to an unauthorized actor, and represents a failure in the principle of least privilege within network management protocols.
The operational impact of this vulnerability extends beyond simple credential theft, as it provides attackers with persistent access to industrial control systems that may control critical infrastructure operations. Remote attackers can leverage these exposed credentials to establish unauthorized sessions, potentially leading to system compromise, operational disruption, or even physical safety risks in environments where these devices control industrial processes. The vulnerability affects devices that are commonly deployed in manufacturing, energy, and utility environments where network security is paramount. Attackers could use the stolen credentials to perform administrative functions, modify system configurations, or gain access to other networked devices within the same network segment.
Mitigation strategies should focus on immediate network segmentation and access control implementation to prevent unauthorized SNMP access to these devices. Network administrators should disable SNMPv1 and SNMPv2c if possible, and implement SNMPv3 with strong authentication and encryption mechanisms. The affected devices should be updated with firmware patches that properly implement access controls for sensitive MIB objects, ensuring that credential information is not exposed through standard SNMP queries. Additionally, network monitoring should be enhanced to detect anomalous SNMP traffic patterns that may indicate exploitation attempts. This vulnerability aligns with ATT&CK technique T1071.004, which covers protocol tunneling and network protocol analysis, as attackers can leverage standard network management protocols to extract sensitive information. Organizations should also implement regular vulnerability assessments and penetration testing to identify similar exposure points within their industrial control system networks, as this type of flaw often indicates broader security configuration issues that may affect other networked devices in the same environment.