CVE-2021-3252 in XP100U
Summary
by MITRE • 02/23/2021
KACO New Energy XP100U Up to XP-JAVA 2.0 is affected by incorrect access control. Credentials will always be returned in plain-text from the local server during the KACO XP100U authentication process, regardless of whatever passwords have been provided, which leads to an information disclosure vulnerability.
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Analysis
by VulDB Data Team • 03/04/2021
The vulnerability identified as CVE-2021-3252 affects KACO New Energy XP100U solar inverters running firmware versions up to XP-JAVA 2.0, representing a critical access control flaw that fundamentally undermines the security posture of these industrial devices. This issue manifests during the authentication process where the local server fails to properly validate credentials and instead consistently returns authentication credentials in plaintext format, regardless of the actual password provided by the user. The flaw demonstrates a fundamental breakdown in the authentication mechanism that violates basic security principles and creates a direct pathway for unauthorized access to sensitive system information.
The technical implementation of this vulnerability stems from improper credential handling within the XP100U's authentication subsystem, where the system does not properly validate user input or enforce access control policies. According to CWE-312, this represents a classic case of exposure of sensitive data through improper handling of credentials, specifically exposing plaintext passwords during authentication. The vulnerability exists at the application level within the local server component that manages user authentication, where the system architecture fails to implement proper cryptographic protection for sensitive data elements. This flaw operates at the intersection of CWE-287, which addresses authentication failures, and CWE-522, which covers insufficiently protected credentials, creating a compound security weakness that affects both the authentication process and credential storage mechanisms.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a persistent security risk that can be exploited by attackers with physical or network access to the device. An attacker who gains access to the local server can immediately obtain plaintext credentials, which may include administrative passwords, system access keys, or other sensitive authentication tokens that could be used to escalate privileges or gain unauthorized control of the solar inverter system. This vulnerability is particularly concerning in industrial environments where these devices are often deployed in remote locations with limited physical security measures, making them attractive targets for attackers seeking to compromise renewable energy infrastructure. The disclosed information could enable attackers to perform unauthorized configuration changes, access system logs, or manipulate operational parameters that affect power generation and grid integration.
Security professionals should implement immediate mitigations including network segmentation to isolate affected devices from critical network segments, deployment of intrusion detection systems to monitor for credential exposure attempts, and implementation of network access controls to restrict unauthorized access to the local server interfaces. Organizations should also conduct comprehensive inventory assessments to identify all affected XP100U devices and prioritize remediation efforts based on risk exposure. The vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and T1566 which covers credential harvesting, indicating that attackers could leverage this flaw to establish persistent access and potentially move laterally within affected networks. Additionally, this vulnerability demonstrates the importance of proper input validation and credential handling in embedded systems, as outlined in the OWASP Top 10 2021 under A07:2021 - Identification and Authentication Failures, which emphasizes that authentication mechanisms must properly validate credentials and protect sensitive information throughout the authentication lifecycle.