CVE-2018-7810 in M340
Summary
by MITRE
An Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability exists in the embedded web servers in all Modicon M340, Premium, Quantum PLCs and BMXNOR0200 allowing an attacker to craft a URL containing JavaScript that will be executed within the user's browser, potentially impacting the machine the browser is running on.
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Analysis
by VulDB Data Team • 04/16/2020
The CVE-2018-7810 vulnerability represents a critical cross-site scripting flaw in the embedded web servers of several Modicon PLC models including M340, Premium, Quantum series, and BMXNOR0200 devices. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically addressing improper neutralization of input during web page generation. The flaw exists within the web server implementation of these industrial control devices, which are widely deployed in critical infrastructure environments for process control and automation. These PLCs typically serve as the backbone of industrial control systems where security is paramount, yet they expose web interfaces that are susceptible to this particular class of attack.
The technical implementation of this vulnerability stems from the embedded web server's failure to properly sanitize user input parameters before incorporating them into dynamically generated web pages. When an attacker crafts a malicious URL containing JavaScript code, the web server processes this input without adequate validation or sanitization mechanisms. The vulnerable web server then embeds this unfiltered input directly into the HTML response sent to the victim's browser, creating a persistent XSS vector. This flaw is particularly dangerous because it allows attackers to execute arbitrary JavaScript code within the context of the victim's browser session, potentially enabling full browser compromise and subsequent attacks on the underlying system.
The operational impact of CVE-2018-7810 extends beyond simple web interface compromise, as it creates opportunities for attackers to escalate their privileges and potentially gain unauthorized access to the industrial control systems. In industrial environments, these PLCs often serve as gateways to critical processes, and a compromised web interface could lead to unauthorized process control commands, data exfiltration, or even physical system manipulation. The vulnerability is particularly concerning in environments where these devices are connected to the internet or where network segmentation is inadequate, as it provides an entry point for attackers to move laterally within the industrial network. The attack vector requires minimal sophistication, making it accessible to threat actors with basic web application exploitation knowledge.
Mitigation strategies for CVE-2018-7810 should include immediate implementation of network segmentation to isolate affected PLCs from general network access, ensuring that only authorized personnel can reach these devices through secure channels. Network administrators should implement web application firewalls and content filtering mechanisms to detect and block malicious input patterns before they reach the vulnerable web servers. Device vendors should be consulted for firmware updates and patches specifically addressing this vulnerability, as Siemens has released security advisories and firmware updates for affected Modicon PLC models. Additionally, regular security assessments should include web interface testing to identify similar vulnerabilities in other industrial control system components. The implementation of secure coding practices and input validation should be enforced across all embedded web server implementations in industrial environments. Organizations should also consider implementing monitoring solutions to detect anomalous web traffic patterns that may indicate exploitation attempts. This vulnerability highlights the importance of securing industrial control system interfaces and demonstrates how traditional web application security flaws can have significant implications in industrial environments where system integrity is critical for operational safety and security.