CVE-2018-20400 in DVW2108
Summary
by MITRE
Ubee DVW2108 6.28.1017 and DVW2110 6.28.2012 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-2018-20400 affects Ubee DVW2108 and DVW2110 wireless routers running firmware versions 6.28.1017 and 6.28.2012 respectively. This issue represents a critical information disclosure flaw that allows remote attackers to extract sensitive authentication credentials through Simple Network Management Protocol (SNMP) queries. The vulnerability specifically targets the management interface of these devices by exposing credential information through two particular SNMP object identifiers that correspond to administrative passwords and usernames within the device configuration. The affected devices are configured with default SNMP community strings that remain unchanged in the factory settings, creating an attack surface that can be exploited by any remote adversary who can access the network.
The technical flaw stems from improper configuration of SNMP services on these network devices, where the Simple Network Management Protocol implementation fails to properly restrict access to sensitive configuration parameters. The two exposed 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 directly map to the administrative username and password fields respectively, allowing attackers to retrieve these credentials without requiring authentication. This represents a direct violation of the principle of least privilege and demonstrates poor security configuration management. The vulnerability is categorized under CWE-200 Information Exposure, which occurs when a system exposes sensitive information to unauthorized parties. The flaw is particularly concerning because it allows for unauthenticated remote access to administrative credentials, potentially enabling full device compromise and subsequent network infiltration.
The operational impact of this vulnerability extends beyond simple credential theft, as it provides attackers with complete administrative control over the affected routers. Once credentials are obtained, attackers can modify network configurations, redirect traffic, implement man-in-the-middle attacks, or establish persistent backdoors within the network infrastructure. The attack surface is particularly broad given that these devices are commonly deployed in residential and small office environments where network monitoring is minimal. The vulnerability can be exploited by any attacker with network access, making it a significant risk to organizations that have these devices in their network infrastructure. According to ATT&CK framework, this vulnerability maps to T1071.004 Application Layer Protocol: DNS and T1078 Valid Accounts, where attackers can leverage the discovered credentials to maintain persistent access to network resources. The exposure of administrative credentials through SNMP also violates NIST SP 800-53 controls related to access control and system configuration management.
Mitigation strategies for CVE-2018-20400 require immediate implementation of network segmentation and access control measures. Organizations should disable SNMP services on affected devices or at minimum restrict SNMP access to trusted management stations using IP address filtering. The most effective remediation involves changing default SNMP community strings to complex, unique values and implementing SNMPv3 with proper authentication and encryption. Network administrators should also conduct comprehensive inventory audits to identify all affected devices and ensure firmware updates are applied where available. The vulnerability highlights the importance of regular security assessments and proper network device hardening practices. Additionally, implementing network monitoring solutions that can detect anomalous SNMP traffic patterns will help identify potential exploitation attempts. Security teams should also consider implementing network access control lists and firewall rules to prevent unauthorized access to SNMP ports on these devices, particularly in environments where physical security is insufficient to prevent unauthorized network access.