CVE-2018-20445 in DCM-604
Summary
by MITRE
D-Link DCM-604 DCM604_C1_ViaCabo_1.04_20130606 and DCM-704 EU_DCM-704_1.10 devices allow remote attackers to discover Wi-Fi credentials via iso.3.6.1.4.1.4413.2.2.2.1.5.4.1.14.1.3.32 and iso.3.6.1.4.1.4413.2.2.2.1.5.4.2.4.1.2.32 SNMP requests.
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Analysis
by VulDB Data Team • 04/24/2020
The vulnerability identified as CVE-2018-20445 affects D-Link DCM-604 and DCM-704 cable modem devices running specific firmware versions. These devices are part of the DOCSIS 3.0 compliant cable modem infrastructure used in broadband internet access deployments. The flaw resides in the Simple Network Management Protocol implementation which allows unauthorized remote attackers to extract sensitive Wi-Fi credentials through specifically crafted SNMP requests. This represents a critical security weakness in network infrastructure devices that handle sensitive authentication information.
The technical implementation of this vulnerability stems from improper access control within the SNMP MIB (Management Information Base) structure of the affected devices. Attackers can exploit the oid paths iso.3.6.1.4.1.4413.2.2.2.1.5.4.1.14.1.3.32 and iso.3.6.1.4.1.4413.2.2.2.1.5.4.2.4.1.2.32 to retrieve wireless network credentials without proper authentication. The vulnerability maps to CWE-284 Access Control Issues, specifically allowing unauthorized information disclosure through network management protocols. These OID paths correspond to internal configuration parameters that should remain protected but are accessible through standard SNMP read operations. The flaw demonstrates poor privilege separation and inadequate input validation within the SNMP service implementation.
The operational impact of this vulnerability is severe as it allows attackers to gain unauthorized access to wireless network credentials used for customer internet connectivity. This compromises not only the confidentiality of network access information but also potentially enables further lateral movement within the network infrastructure. The attack can be executed remotely without requiring physical access or prior authentication, making it particularly dangerous for network administrators who may not immediately detect unauthorized access to sensitive configuration data. The vulnerability affects both the DCM-604 and DCM-704 models, representing a significant exposure across multiple device variants in the D-Link cable modem product line. This issue directly aligns with ATT&CK technique T1071.004 Application Layer Protocol: DNS where attackers could leverage the compromised credentials for further network reconnaissance and access.
Mitigation strategies should focus on immediate firmware updates from D-Link to address the SNMP access control weakness. Network administrators should implement SNMP access control lists to restrict SNMP queries to authorized management systems only. The configuration of the affected devices should be reviewed to ensure that only necessary SNMP services are enabled and that community strings are properly secured. Network segmentation and monitoring should be implemented to detect unauthorized SNMP access attempts. Additionally, the use of SNMPv3 with strong authentication and encryption should be considered as a replacement for SNMPv1 or v2c implementations. The vulnerability highlights the importance of proper network device hardening and regular security assessments of infrastructure equipment. Organizations should also consider implementing network access control measures that prevent unauthorized devices from accessing management interfaces. This vulnerability serves as a reminder of the critical importance of securing network management protocols and the potential consequences of inadequate access control implementations in network infrastructure devices.