CVE-2018-6908 in RainMachine Mini-8
Summary
by MITRE
An authentication bypass vulnerability exists in the Green Electronics RainMachine Mini-8 (2nd Generation) and Touch HD 12 web application allowing an unauthenticated attacker to perform authenticated actions on the device via a 127.0.0.1:port value in the HTTP 'Host' header, as demonstrated by retrieving credentials.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 04/09/2020
The vulnerability identified as CVE-2018-6908 represents a critical authentication bypass flaw in Green Electronics RainMachine devices, specifically affecting the Mini-8 (2nd Generation) and Touch HD 12 models. This weakness stems from improper handling of the HTTP Host header parameter within the web application interface, creating a pathway for unauthorized access to privileged functions. The vulnerability allows attackers to exploit a localhost binding mechanism by manipulating the HTTP Host header to include a 127.0.0.1:port value, effectively circumventing the authentication requirements that should normally protect sensitive device operations and configuration settings.
The technical implementation of this flaw involves the web application's failure to properly validate and sanitize the Host header input, which is commonly used by web servers to determine which virtual host should handle incoming requests. When an attacker crafts a malicious HTTP request with a Host header containing the localhost address, the application incorrectly interprets this as a legitimate internal request rather than an external attack attempt. This misinterpretation occurs because the device's web interface does not properly validate that the Host header originates from an authenticated session or trusted source, allowing the attacker to execute authenticated operations without proper credentials. The vulnerability specifically affects the device's web application layer and leverages the trust relationship that exists between internal components and the localhost address.
The operational impact of this vulnerability is severe as it enables an unauthenticated attacker to perform any action that would normally require valid authentication credentials. This includes accessing sensitive device configuration data, modifying system settings, retrieving stored credentials, and potentially gaining full administrative control over the device. The attack vector is particularly concerning because it requires no prior authentication credentials and can be executed remotely, making it accessible to attackers on the same network segment or potentially even from outside the network if port forwarding or other network traversal techniques are employed. The ability to retrieve credentials represents a particularly dangerous aspect as it provides attackers with legitimate access tokens that can be used to escalate their privileges or access other systems within the network infrastructure.
Security professionals should recognize this vulnerability as a classic example of improper input validation and trust boundary violations, aligning with CWE-285 (Improper Authorization) and CWE-290 (Authentication Bypass by Spoofing) categories. The attack pattern follows techniques described in the MITRE ATT&CK framework under T1078 (Valid Accounts) and T1046 (Network Service Scanning) as attackers can leverage this bypass to gain access to legitimate accounts and system resources. Organizations using these RainMachine devices should implement immediate mitigations including network segmentation to isolate these devices from untrusted networks, implementing proper firewall rules to restrict access to the web interface, and updating firmware to versions that properly validate Host header inputs. Additionally, network monitoring should be enhanced to detect suspicious Host header values that may indicate exploitation attempts, and access to these devices should be restricted to authenticated users only through secure remote access solutions rather than direct internet exposure.