CVE-2018-4834 in PXC
Summary
by MITRE
A vulnerability has been identified in Desigo Automation Controllers Compact PXC12/22/36-E.D, Desigo Automation Controllers Modular PXC00/50/100/200-E.D, Desigo Automation Controllers PXC00/64/128-U with Web module, Desigo Automation Controllers for Integration PXC001-E.D, Desigo Operator Unit PXM20-E. A remote attacker with network access to the device could potentially upload a new firmware image to the devices without prior authentication.
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Analysis
by VulDB Data Team • 02/02/2023
This vulnerability represents a critical security flaw in Schneider Electric's Desigo automation controllers, specifically affecting multiple device models including compact and modular series with web modules. The vulnerability stems from insufficient authentication mechanisms during firmware update processes, allowing unauthenticated remote attackers to upload malicious firmware images to affected devices. This represents a fundamental failure in the device's security architecture where the update mechanism lacks proper access controls and verification procedures. The flaw enables attackers to bypass normal security protocols and potentially gain persistent control over industrial automation systems through unauthorized firmware modifications.
The technical implementation of this vulnerability involves a weakness in the device's web interface firmware update functionality where authentication checks are either absent or easily bypassed. Attackers can exploit this by sending specially crafted requests to the device's update endpoint without requiring valid credentials or authorization tokens. This vulnerability falls under the CWE-305 authentication weakness category, specifically related to insufficient authentication mechanisms. The flaw operates at the application layer of the network stack where the web server component fails to properly validate user credentials before accepting firmware upload requests. According to ATT&CK framework, this represents a privilege escalation technique through software supply chain compromise, where the attacker can modify legitimate software components to gain unauthorized access.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to potentially compromise entire industrial control systems by installing malicious firmware that could persist even after device reboots. This creates a persistent backdoor within the automation infrastructure, allowing attackers to maintain long-term access while potentially manipulating industrial processes. The affected devices operate in critical infrastructure environments where unauthorized firmware modifications could lead to operational disruptions, safety hazards, or even physical damage to industrial equipment. The vulnerability affects devices that are commonly deployed in manufacturing, energy, and building automation environments where maintaining system integrity and security is paramount. Organizations using these controllers face significant risk of supply chain attacks where malicious firmware could be used to monitor communications, manipulate process controls, or create denial-of-service conditions.
Mitigation strategies should include immediate network segmentation to isolate affected devices from general network access, implementation of strict firewall rules to restrict access to device management interfaces, and mandatory firmware update procedures that include cryptographic verification of update images. Device administrators should disable unnecessary web interfaces when not required, implement strong access controls with multi-factor authentication, and conduct regular security assessments of industrial control systems. The vulnerability highlights the importance of secure firmware update mechanisms in industrial environments and aligns with NIST cybersecurity frameworks for critical infrastructure protection. Organizations should also consider implementing network monitoring solutions to detect anomalous firmware update activities and establish incident response procedures specifically tailored for industrial control system security breaches. Regular security updates and patch management processes should be implemented to address similar vulnerabilities in other industrial control system components.