CVE-2018-20385 in CBV38Z4EC
Summary
by MITRE
CastleNet CBV38Z4EC 125.553mp1.39219mp1.899.007, CBV38Z4ECNIT 125.553mp1.39219mp1.899.005ITT, CBW383G4J 37.556mp5.008, and CBW38G4J 37.553mp1.008 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-2018-20385 affects several CastleNet network devices including the CBV38Z4EC, CBV38Z4ECNIT, CBW383G4J, and CBW38G4J models. These devices are network infrastructure components that utilize SNMP (Simple Network Management Protocol) for management and monitoring purposes. The flaw resides in how these devices handle specific SNMP GET requests targeting MIB (Management Information Base) objects related to credentials. The affected SNMP 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 are designed to retrieve sensitive information but are improperly configured to return authentication credentials without adequate access controls or authentication mechanisms. This represents a critical security weakness that violates fundamental principles of information security and access control.
The technical implementation of this vulnerability stems from inadequate input validation and insufficient privilege checking within the SNMP service implementation of these devices. When remote attackers send specially crafted SNMP GET requests to these specific OIDs, the devices respond by disclosing sensitive credential information including usernames and passwords. The vulnerability is classified under CWE-200 (Information Exposure) and CWE-287 (Improper Authentication) according to the Common Weakness Enumeration taxonomy. This allows attackers to gain unauthorized access to network devices and potentially escalate their privileges within the network infrastructure. The flaw is particularly concerning because it enables remote credential disclosure without requiring any authentication or network access privileges, making it highly exploitable by malicious actors with network connectivity to the affected devices.
The operational impact of this vulnerability extends beyond simple credential theft and represents a significant risk to network security posture. Attackers who successfully exploit this vulnerability can gain full administrative access to the affected network devices, potentially leading to complete network compromise. This aligns with ATT&CK technique T1078 (Valid Accounts) and T1566 (Phishing for Information) as attackers can leverage stolen credentials to move laterally within the network or establish persistent access. The vulnerability affects network infrastructure that is typically considered critical for maintaining network operations, meaning that compromise of these devices can result in widespread service disruption, data interception, and unauthorized network access. Organizations using these devices face potential exposure to advanced persistent threats and insider attack scenarios where attackers can maintain long-term access to their network infrastructure.
Mitigation strategies for this vulnerability should focus on immediate network segmentation and access control implementation. Network administrators should disable SNMPv1 and SNMPv2c protocols on affected devices and migrate to SNMPv3 which provides stronger authentication and encryption mechanisms. The affected devices should be updated with firmware patches provided by CastleNet or the vendor, as these patches typically address the improper credential handling in SNMP responses. Network monitoring should be enhanced to detect unusual SNMP traffic patterns and unauthorized access attempts to the specific vulnerable OIDs. Additional security measures include implementing network access control lists to restrict SNMP access to trusted management stations only, disabling unnecessary SNMP services, and conducting regular security assessments of network infrastructure components. Organizations should also establish procedures for monitoring and responding to potential exploitation attempts, as the vulnerability can be exploited by automated scanning tools that continuously probe for known weaknesses in network devices.