CVE-2018-6011 in RainMachine Mini-8
Summary
by MITRE
The time-based one-time-password (TOTP) function in the application logic of the Green Electronics RainMachine Mini-8 (2nd generation) uses the administrator's password hash to generate a 6-digit temporary passcode that can be used for remote and local access, aka a "Use of Password Hash Instead of Password for Authentication" issue. This is exploitable by an attacker who discovers a hash value in the rainmachine-settings.sqlite file.
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Analysis
by VulDB Data Team • 04/09/2020
The vulnerability described in CVE-2018-6011 represents a critical authentication flaw in the Green Electronics RainMachine Mini-8 (2nd generation) device that fundamentally undermines the security model of the system. This device, designed for smart irrigation control, implements a time-based one-time-password mechanism that should provide temporary access credentials but instead relies on the administrator's password hash as the core component for generating these temporary passcodes. The flaw lies in the application logic where the system uses the password hash directly rather than the actual password, creating a scenario where an attacker who gains access to the device's internal storage can extract authentication credentials without needing to perform brute force attacks or other complex exploitation techniques.
The technical implementation of this vulnerability stems from a design decision that violates fundamental security principles regarding credential handling and authentication mechanisms. The rainmachine-settings.sqlite file contains the password hash in a format that can be extracted by an attacker with access to the device's file system. This represents a classic case of improper authentication implementation where the system fails to properly separate the authentication components and instead uses a cryptographic hash of the password as the basis for generating temporary authentication tokens. The vulnerability directly maps to CWE-521 Weak Password Requirements and CWE-287 Improper Authentication, both of which are categorized under the broader category of authentication weaknesses that can lead to unauthorized access.
The operational impact of this vulnerability is severe as it allows attackers to gain both remote and local administrative access to the irrigation system without requiring knowledge of the actual password. This creates a significant risk for users who rely on the device for automated water management in residential or commercial settings. The temporary passcodes generated through this flawed mechanism can be used repeatedly and indefinitely, as they are derived from the permanent password hash rather than being time-limited or session-specific. Attackers can exploit this vulnerability by simply extracting the hash from the sqlite database file, which can be accomplished through various means including physical access to the device, network-based attacks, or by exploiting other vulnerabilities in the device's firmware that allow for file system access.
This vulnerability also creates additional security concerns when considering the broader ATT&CK framework for adversary tactics and techniques. The ability to extract authentication credentials from the device's internal storage aligns with the ATT&CK technique T1003.001 Credential Dumping: LSASS Memory, though in this case the credentials are stored in a database file rather than memory. The flaw also enables techniques related to privilege escalation and lateral movement within networks where these devices might be connected, as the attacker can maintain persistent access to the irrigation system. The device's role in automated systems makes it particularly attractive to attackers who might seek to disrupt operations, access sensitive environmental data, or use the device as a foothold for accessing other connected systems within the same network infrastructure.
Mitigation strategies for this vulnerability require immediate attention from both device manufacturers and end users. The primary remediation involves updating the device firmware to implement proper authentication mechanisms that do not rely on password hashes for generating temporary passcodes. The system should be redesigned to use time-based one-time passwords that are generated independently of any stored password information, potentially through the use of secure random number generation or hardware security modules. Additionally, users should implement network segmentation to isolate these devices from critical network infrastructure and regularly monitor for unauthorized access attempts. The vulnerability highlights the importance of proper credential management and authentication design principles, emphasizing that password hashes should never be used as the basis for generating authentication tokens, particularly in systems where the hash might be accessible to unauthorized parties. Organizations should also consider implementing additional security controls such as network access controls, intrusion detection systems, and regular security assessments to identify and remediate similar vulnerabilities in IoT devices.