CVE-2021-34578 in 750-362
Summary
by MITRE • 08/31/2021
This vulnerability allows an attacker who has access to the WBM to read and write settings-parameters of the device by sending specifically constructed requests without authentication on multiple WAGO PLCs in firmware versions up to FW07.
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Analysis
by VulDB Data Team • 09/03/2021
The vulnerability identified as CVE-2021-34578 represents a critical security flaw in WAGO programmable logic controllers that exposes unauthorized access to device configuration parameters through unauthenticated remote requests. This weakness specifically affects WAGO PLCs operating on firmware versions up to FW07 and allows attackers with access to the WAGO Web Based Management (WBM) interface to manipulate system settings without proper authentication credentials. The vulnerability stems from insufficient access controls within the web management interface, creating a pathway for malicious actors to bypass standard authentication mechanisms and gain unauthorized control over critical industrial control systems.
The technical implementation of this vulnerability involves the exploitation of improper input validation and access control mechanisms within the WAGO WBM service. Attackers can construct specifically formatted HTTP requests that target the device configuration parameters, enabling them to read sensitive system information and modify operational settings. This flaw operates at the application layer and leverages the inherent trust placed in the WAGO management interface, allowing attackers to perform actions such as changing network configurations, modifying security parameters, and altering operational settings that could disrupt industrial processes. The vulnerability is particularly concerning because it does not require authentication to execute, making it accessible to anyone with network access to the device and knowledge of the specific request structure.
The operational impact of CVE-2021-34578 extends beyond simple unauthorized access, as it can lead to significant disruptions in industrial control environments where WAGO PLCs are deployed. An attacker could potentially manipulate critical control parameters, leading to process failures, safety system compromises, or even physical damage to industrial equipment. The vulnerability affects multiple WAGO PLC models, amplifying its potential impact across various industrial sectors including manufacturing, energy, and process control environments. This exposure creates opportunities for attackers to establish persistent access points, escalate privileges, or conduct more sophisticated attacks such as those targeting the industrial control system infrastructure. The vulnerability's presence in firmware versions up to FW07 indicates that a substantial portion of deployed WAGO PLCs remain at risk, particularly in legacy installations where firmware updates may not be regularly applied.
Organizations should implement immediate mitigations including network segmentation to isolate WAGO PLCs from general network access, disabling unnecessary web management interfaces, and applying firmware updates as provided by WAGO. The vulnerability aligns with CWE-284, which addresses improper access control, and can be mapped to ATT&CK techniques such as T1071.004 for application layer protocol manipulation and T1059.001 for command and scripting interpreter usage. Security monitoring should focus on detecting anomalous web requests to WAGO management interfaces and unusual parameter changes in industrial control systems. Regular security assessments and vulnerability scanning should be conducted to identify affected devices and ensure proper access controls are in place. The remediation strategy should include comprehensive firmware updates, network access controls, and security awareness training for personnel managing industrial control systems to prevent exploitation of this critical vulnerability.