CVE-2017-9853 in Solar System
Summary
by MITRE
An issue was discovered in SMA Solar Technology products. All inverters have a very weak password policy for the user and installer password. No complexity requirements or length requirements are set. Also, strong passwords are impossible due to a maximum of 12 characters and a limited set of characters.
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Analysis
by VulDB Data Team • 08/05/2024
The vulnerability identified as CVE-2017-9853 represents a critical weakness in SMA Solar Technology products that significantly compromises the security posture of solar inverter systems. This issue affects all inverters within the SMA Solar product line and stems from a fundamental flaw in the authentication mechanism design. The weakness manifests through an inadequate password policy implementation that fails to enforce any complexity or length requirements for user and installer credentials. This vulnerability directly violates established security best practices and represents a clear deviation from industry standards for credential management.
The technical flaw in question resides in the password policy configuration of SMA Solar inverters, where the system imposes no constraints on password complexity or minimum length requirements. The implementation restricts passwords to a maximum of twelve characters while simultaneously limiting the character set available for password construction. This dual limitation creates an environment where attackers can easily enumerate or guess valid credentials through brute force methods or dictionary attacks. The constrained character set typically includes only alphanumeric characters without special symbols, significantly reducing the entropy of potential passwords and making them susceptible to automated cracking tools. This weakness creates a predictable and exploitable authentication mechanism that undermines the fundamental security of the entire solar installation.
The operational impact of this vulnerability extends beyond simple credential guessing to encompass broader security implications for solar energy installations. Attackers who successfully exploit this weakness can gain unauthorized access to inverter systems, potentially allowing them to modify operational parameters, disrupt power generation, or even cause physical damage to the installation. The vulnerability affects both user and installer accounts, meaning that unauthorized individuals could potentially access critical system controls or configuration settings. This access could enable attackers to manipulate power output, disable security features, or gain persistence within the installation network. The implications are particularly concerning for large-scale solar installations where multiple inverters may be interconnected and where unauthorized access could compromise entire energy generation systems.
From a cybersecurity perspective, this vulnerability aligns with CWE-521 Weak Password Requirements, which specifically addresses the lack of sufficient password strength controls. The issue also maps to ATT&CK technique T1110.003 Credential Stuffing, as the weak password policy makes systems vulnerable to automated credential brute force attacks. The limited character set and maximum length restrictions create an environment where attackers can efficiently test password combinations using automated tools. Organizations implementing SMA Solar technology should consider this vulnerability in their risk assessments and security monitoring activities. The remediation approach should focus on implementing strong password policies that enforce minimum length requirements, character set diversity, and regular password rotation. Additionally, network segmentation and multi-factor authentication mechanisms should be implemented to provide additional layers of protection against unauthorized access attempts.