CVE-2018-20381 in DPC2320
Summary
by MITRE
Technicolor DPC2320 dpc2300r2-v202r1244101-150420a-v6 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 CVE-2018-20381 affects Technicolor DPC2320 and DPC2300R2 devices running specific firmware versions, presenting a critical security flaw in the Simple Network Management Protocol implementation. This issue allows remote attackers to extract sensitive authentication credentials through carefully crafted SNMP requests targeting specific Object Identifiers within the device's management interface. The affected devices utilize SNMPv1 or SNMPv2c protocols which lack proper authentication mechanisms and encryption, creating an attack surface that can be exploited without requiring prior authentication or network access privileges. The vulnerability specifically targets the 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 OID paths, which expose administrative credentials and system configuration data that should remain protected within the device's private management information base.
The technical exploitation of this vulnerability stems from insufficient access controls within the SNMP implementation of these broadband routers and modems. The affected SNMP MIB (Management Information Base) structures contain readable password fields and administrative access credentials that are improperly protected by authentication mechanisms. Attackers can simply send SNMP GET requests to the vulnerable OIDs without requiring valid credentials, causing the device to respond with plaintext credentials that are stored in the device's memory and accessible through the standard SNMP protocol. This represents a classic information disclosure vulnerability where sensitive data is exposed through improper access control mechanisms, making it particularly dangerous as it allows attackers to gain unauthorized access to device management interfaces. The flaw falls under CWE-200, Information Exposure, and more specifically CWE-552, Information Exposure Through Directory Listing, as it allows unauthorized access to system configuration data through network protocols.
The operational impact of this vulnerability extends beyond simple credential theft, as it provides attackers with complete administrative control over the affected devices. Once credentials are obtained, attackers can modify device configurations, disable security features, redirect traffic, or establish persistent access points within the network. The vulnerability affects both residential and enterprise network environments where these devices are commonly deployed, potentially allowing attackers to compromise entire network infrastructures. The attack vector is particularly concerning because it requires no physical access to the device, operates over standard network protocols, and can be executed from anywhere on the internet. This vulnerability aligns with ATT&CK technique T1071.004, Application Layer Protocol: DNS, as attackers may use DNS queries to identify vulnerable devices, and T1046, Network Service Scanning, to discover devices running the vulnerable firmware. The exposure of administrative credentials also enables further attacks such as privilege escalation, lateral movement, and persistence establishment within the network.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The primary recommendation involves updating device firmware to versions that properly secure SNMP access controls and remove the exposed credential fields from public SNMP queries. Network administrators should disable SNMPv1 and SNMPv2c protocols entirely and migrate to SNMPv3, which provides proper authentication and encryption mechanisms. Additionally, network segmentation should be implemented to isolate these devices from critical network segments, and access controls should be enforced through firewalls to restrict SNMP traffic to trusted management networks only. The implementation of network monitoring solutions that can detect anomalous SNMP traffic patterns and credential exposure attempts is also essential. Organizations should conduct comprehensive vulnerability assessments to identify other devices that may be running similar firmware versions and apply patches or security updates accordingly. This vulnerability demonstrates the importance of proper protocol configuration and the necessity of regularly updating network device firmware to address known security flaws that can be exploited remotely by threat actors without requiring specialized tools or significant technical expertise.