CVE-2018-20382 in BCM93383WRG
Summary
by MITRE
Jiuzhou BCM93383WRG 139.4410mp1.3921132mp1.899.004404.004 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-2018-20382 affects Jiuzhou BCM93383WRG network devices running firmware versions 139.4410mp1.3921132mp1.899.004404.004. This represents a critical security flaw in the device's SNMP implementation that exposes sensitive authentication credentials to remote attackers. The vulnerability specifically targets the device's Simple Network Management Protocol configuration, which is commonly used for network monitoring and management purposes. The affected devices are part of the Jiuzhou BCM93383WRG series, which are typically deployed in enterprise networking environments where SNMP is extensively utilized for device management and monitoring functions. This particular vulnerability stems from improper handling of SNMP GET requests that should not be returning credential information in plaintext format.
The technical flaw manifests through the exposure of sensitive credential data via specific SNMP object identifiers within the device's management interface. Attackers can exploit this vulnerability by sending carefully crafted SNMP GET requests to 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 OIDs, which are part of the device's MIB (Management Information Base) structure. These OIDs correspond to authentication credentials that should remain protected within the device's secure management interface. The vulnerability falls under CWE-200, which describes information exposure through improper access control, and specifically relates to CWE-772, which covers missing release of resource after effective lifetime. The flaw represents a classic case of insecure SNMP implementation where the device fails to properly validate and restrict access to sensitive management information, allowing unauthorized parties to extract authentication data through standard network protocols.
The operational impact of this vulnerability extends far beyond simple credential exposure, as it provides attackers with a direct pathway to gain unauthorized access to network management functions and potentially the entire network infrastructure. Once credentials are obtained through this SNMP-based attack vector, adversaries can perform a wide range of malicious activities including but not limited to network reconnaissance, privilege escalation, and lateral movement within the compromised network. The vulnerability is particularly dangerous because SNMP is often enabled by default on network devices and frequently configured with weak or default authentication credentials. This exposure creates a significant risk for enterprise environments where network devices are managed through SNMP protocols, as it allows attackers to compromise device management functions and potentially gain control over critical network infrastructure. The attack can be executed remotely without requiring physical access or specialized equipment, making it an attractive target for both opportunistic and targeted attacks.
The mitigation strategies for this vulnerability should focus on immediate network segmentation and access control implementation to prevent unauthorized SNMP access. Organizations should disable SNMPv1 and SNMPv2c protocols where possible and migrate to SNMPv3 which provides stronger authentication and encryption mechanisms. Network administrators must implement proper SNMP community string management with unique, complex credentials for each device and ensure that SNMP access is restricted to authorized management stations only. The implementation of network access control lists and firewall rules to limit SNMP traffic to trusted management systems is essential. Additionally, regular firmware updates should be applied to address the underlying vulnerability in the Jiuzhou BCM93383WRG devices, as this specific issue has been addressed in subsequent firmware releases. Security monitoring should include detection of anomalous SNMP traffic patterns and unauthorized access attempts to management information bases, as outlined in the ATT&CK framework's T1071.004 technique for application layer protocol: dns. The vulnerability demonstrates the importance of proper information hiding and access control in network management protocols, as defined by the NIST Cybersecurity Framework's information security principles.