CVE-2021-38412 in PortServer TS 16
Summary
by MITRE • 09/18/2021
Properly formatted POST requests to multiple resources on the HTTP and HTTPS web servers of the Digi PortServer TS 16 Rack device do not require authentication or authentication tokens. This vulnerability could allow an attacker to enable the SNMP service and manipulate the community strings to achieve further control in.
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Analysis
by VulDB Data Team • 09/22/2021
The Digi PortServer TS 16 Rack device presents a critical authentication bypass vulnerability that fundamentally undermines its security posture. This vulnerability resides within the web server implementation of the device, specifically affecting both HTTP and HTTPS protocols. The flaw manifests when properly formatted POST requests are sent to multiple resources on the device's web server interface, allowing unauthorized access without requiring valid authentication credentials or tokens. This represents a severe deviation from standard security practices where authentication mechanisms should consistently validate user credentials before granting access to administrative functions. The vulnerability impacts the device's core security model by creating an unintended access path that bypasses the established authentication framework, effectively rendering the device's authentication controls ineffective.
The technical nature of this vulnerability stems from improper input validation and access control implementation within the device's web server component. When POST requests are received, the system fails to properly verify that the requesting entity has valid authentication credentials before processing the request. This flaw allows attackers to construct specific HTTP POST requests that target various administrative resources within the device's web interface. The vulnerability specifically enables manipulation of the SNMP service configuration, which is a critical component for network monitoring and management. The device's web server implementation does not adequately enforce authentication checks for certain POST endpoints, creating a persistent access vector that remains active across both HTTP and HTTPS protocols. This design flaw represents a failure in the principle of least privilege, where administrative functions should remain protected regardless of the transport protocol used.
The operational impact of this vulnerability is substantial and potentially catastrophic for organizations relying on Digi PortServer TS 16 Rack devices for network infrastructure management. Attackers can exploit this vulnerability to enable SNMP services without proper authorization, which provides them with significant network visibility and control capabilities. The ability to manipulate community strings further amplifies the risk, as SNMP community strings function as passwords for network management access. This vulnerability enables attackers to gain unauthorized access to network monitoring data, potentially allowing them to discover network topology, device configurations, and operational details. The implications extend beyond simple information disclosure to include potential network compromise through SNMP-based attacks, as the community string manipulation could enable further exploitation of network devices. Organizations may face regulatory compliance violations if sensitive network information becomes accessible to unauthorized parties, particularly in environments governed by standards such as pci dss or nist cybersecurity framework.
The vulnerability aligns with common security weaknesses identified in the CWE database, particularly CWE-287 which addresses improper authentication, and CWE-312 which covers exposure of sensitive information. From an ATT&CK framework perspective, this vulnerability maps to TA0001 (Initial Access) and TA0002 (Execution) tactics, as it provides unauthorized access to the device and enables further command execution capabilities. The attack surface is particularly concerning because it affects both HTTP and HTTPS protocols, meaning that even encrypted communications may be vulnerable if the device's web server implementation fails to properly validate authentication across all transport mechanisms. Organizations should consider this vulnerability as part of a broader attack chain where initial access through authentication bypass can lead to privilege escalation and lateral movement within network environments. The risk is compounded by the fact that the vulnerability affects a network infrastructure device, potentially providing attackers with persistent access points for extended network infiltration activities.
Mitigation strategies should focus on immediate firmware updates from Digi to address the authentication bypass implementation flaw. Organizations should also implement network segmentation to limit access to these devices, ensuring that only authorized management systems can reach the device's web interfaces. Additional protective measures include disabling unnecessary services, implementing strong access controls through network firewalls, and monitoring for unauthorized SNMP service activation. The device configuration should enforce strict authentication requirements for all administrative interfaces, regardless of the protocol used. Security teams should conduct thorough network scans to identify all affected devices and implement continuous monitoring for unauthorized configuration changes. Regular security assessments should be performed to ensure that similar authentication bypass vulnerabilities do not exist in other network infrastructure components. Organizations should also establish incident response procedures specifically addressing unauthorized access to network management interfaces, as this vulnerability could indicate broader security compromise attempts within the network infrastructure.