CVE-2018-20393 in CGA0111
Summary
by MITRE
Technicolor CGA0111 CGA0111E-ES-13-E23E-c8000r5712-170217-0829-TRU, CWA0101 CWA0101E-A23E-c7000r5712-170315-SKC, DPC3928SL D3928SL-PSIP-13-A010-c3420r55105-170214a, TC7110.AR STD3.38.03, TC7110.B STC8.62.02, TC7110.D STDB.79.02, TC7200.d1I TC7200.d1IE-N23E-c7000r5712-170406-HAT, and TC7200.TH2v2 SC05.00.22 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
This vulnerability affects multiple Technicolor residential gateway devices including CGA0111, CWA0101, DPC3928SL, TC7110, and TC7200 series models. The flaw resides in the Simple Network Management Protocol implementation where specific SNMP object identifiers 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 accessible without proper authentication mechanisms. These OIDs expose sensitive credential information including administrative passwords and network configuration details through unsecured SNMP queries. The vulnerability represents a critical security weakness that violates fundamental principles of network security and access control as outlined in CWE-284 Access Control.
The technical exploitation occurs through SNMP GET requests targeting the specific MIB (Management Information Base) objects mentioned in the CVE description. Attackers can remotely query these OID values without requiring authentication credentials, effectively bypassing normal access controls. This exposure allows threat actors to obtain administrative passwords, network credentials, and potentially gain full control over the affected devices. The vulnerability stems from improper implementation of SNMP security measures where sensitive information is exposed through public MIB access points. According to ATT&CK framework, this maps to T1071.004 Application Layer Protocol: DNS and T1018 Remote System Discovery, as attackers can enumerate device information and credentials through legitimate network protocols.
The operational impact of this vulnerability is severe for network administrators and end users. Compromised devices can lead to complete network takeover, unauthorized data access, and potential lateral movement within corporate networks. Attackers can leverage these credentials to access internal systems, modify network configurations, or establish persistent backdoors. The vulnerability affects devices deployed in both residential and enterprise environments, making it particularly dangerous as it can be exploited by anyone with network access to the affected devices. This weakness creates a persistent threat vector that can remain undetected for extended periods, allowing attackers to maintain unauthorized access while conducting reconnaissance and further attacks.
Mitigation strategies include immediate disabling of SNMP services on affected devices when not required, implementing proper SNMP community string management with strong authentication, and restricting SNMP access through firewall rules to authorized management stations only. Network segmentation and monitoring should be implemented to detect unauthorized SNMP queries. Device firmware updates from Technicolor should be applied immediately to address the underlying implementation flaw. Security professionals should conduct comprehensive network scans to identify all affected devices and ensure proper SNMP configuration. Additionally, implementing network access control lists and monitoring for unusual SNMP traffic patterns can help detect exploitation attempts. The vulnerability highlights the importance of following security best practices for network management protocols as specified in NIST SP 800-125 and ISO/IEC 27001 controls for information security management.