CVE-2018-20398 in CM5100
Summary
by MITRE
Skyworth CM5100 V1.1.0, CM5100-440 V1.2.1, CM5100-511 4.1.0.14, CM5100-GHD00 V1.2.2, and CM5100.g2 4.1.0.17 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-2018-20398 affects Skyworth CM5100 series network devices including various firmware versions such as V1.1.0, V1.2.1, 4.1.0.14, V1.2.2, and 4.1.0.17. This issue represents a significant security weakness in the device's Simple Network Management Protocol implementation that exposes sensitive authentication information to remote attackers. The vulnerability specifically resides in the device's SNMP (Simple Network Management Protocol) configuration where it inadvertently reveals credential information through specific OID (Object Identifier) requests. The affected 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 serve as entry points for attackers to extract authentication details without requiring legitimate credentials or prior access to the device. This flaw falls under CWE-200, which describes the exposure of sensitive information to an unauthorized actor, and specifically relates to the improper exposure of credentials through network protocols. The vulnerability aligns with ATT&CK technique T1082, which involves discovering system information, and T1552, which focuses on credentials from password storage repositories, as attackers can leverage this information to gain further access to the network infrastructure. The technical implementation flaw stems from the device's failure to properly validate and restrict access to sensitive SNMP MIB (Management Information Base) values that contain authentication parameters. The device configuration does not adequately implement access controls or authentication mechanisms for these specific OIDs, allowing any remote entity to query and retrieve the exposed credential information.
The operational impact of this vulnerability is severe for organizations utilizing Skyworth CM5100 devices in their network infrastructure. Remote attackers can exploit this weakness to obtain administrative credentials that provide full control over the affected devices, potentially enabling them to modify network configurations, implement malicious changes, or use the compromised credentials to pivot into adjacent network segments. The exposure of these credentials creates an immediate threat vector that could lead to complete device compromise and subsequent network infiltration. Attackers could leverage the stolen credentials to gain unauthorized access to the device management interfaces, potentially leading to man-in-the-middle attacks or the ability to manipulate network traffic routing. The vulnerability's remote nature means that attackers do not require physical access to the devices, making the threat surface significantly larger than local attack scenarios. Organizations may experience unauthorized network modifications, data exfiltration, or service disruption if attackers successfully exploit these credentials to compromise the devices. The exposure of administrative credentials through SNMP also increases the risk of credential reuse attacks, where compromised credentials might be used to access other systems within the same network domain that share similar authentication mechanisms.
Mitigation strategies for this vulnerability should prioritize immediate remediation through firmware updates provided by Skyworth, as these devices are likely to have received patches addressing the SNMP credential exposure issue. Organizations should implement network segmentation and access control measures to limit the scope of potential exploitation, ensuring that SNMP traffic is restricted to authorized management systems only. Network administrators should disable SNMPv1 and SNMPv2c protocols where possible, and implement SNMPv3 with strong authentication and encryption mechanisms to prevent unauthorized access to device management interfaces. The configuration of the affected devices should include explicit access control lists that restrict which IP addresses can query specific SNMP OIDs, particularly those containing sensitive information. Regular network monitoring should be implemented to detect unusual SNMP traffic patterns or unauthorized access attempts to the vulnerable OIDs. Security teams should conduct comprehensive vulnerability assessments to identify any other devices within their network that may be running similar firmware versions or exhibiting similar SNMP configuration weaknesses. Additionally, implementing network access control lists and firewalls to restrict SNMP traffic to only trusted management stations will significantly reduce the attack surface. Organizations should also establish credential rotation procedures to ensure that any compromised credentials are promptly invalidated and replaced with new secure authentication information. The implementation of network-based intrusion detection systems can help identify and alert on suspicious SNMP queries targeting the vulnerable OIDs, providing early warning of potential exploitation attempts.