CVE-2018-7804 in M340
Summary
by MITRE
A URL Redirection to Untrusted Site vulnerability exists in the embedded web servers in all Modicon M340, Premium, Quantum PLCs and BMXNOR0200 where a user clicking on a specially crafted link can be redirected to a URL of the attacker's choosing.
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Analysis
by VulDB Data Team • 04/21/2020
The vulnerability identified as CVE-2018-7804 represents a critical security flaw in the embedded web server implementations of several Modicon PLC models including M340, Premium, Quantum series, and BMXNOR0200 devices. This issue manifests as a URL redirection vulnerability that allows attackers to manipulate web browser navigation when users interact with maliciously crafted links. The flaw exists within the web server component of these industrial control systems, which are widely deployed in critical infrastructure environments for process automation and control. The vulnerability specifically affects the embedded web interfaces that provide remote access and configuration capabilities for these programmable logic controllers.
This security weakness stems from inadequate input validation and sanitization within the web server's handling of URL parameters and redirection mechanisms. When users access the web interface of these PLCs and encounter specially crafted links, the system fails to properly validate the destination URLs before initiating redirection. The technical implementation appears to lack proper URL validation routines that would normally check for malicious redirection targets or enforce trusted domain restrictions. This allows an attacker to craft links that redirect users to arbitrary web addresses controlled by the attacker, potentially leading to phishing attacks, credential harvesting, or further exploitation of the industrial control environment.
The operational impact of this vulnerability extends beyond simple web redirection and represents a significant risk to industrial control system security. In critical infrastructure environments, these PLCs often serve as fundamental components of operational technology networks where unauthorized access can lead to severe consequences including process disruption, safety hazards, and potential physical damage to equipment. The vulnerability enables attackers to establish initial footholds within industrial networks through social engineering tactics, as users may be tricked into clicking malicious links that appear legitimate. This represents a classic attack vector that aligns with the tactics described in the attack pattern taxonomy under the MITRE ATT&CK framework for initial access through social engineering and phishing techniques.
Organizations operating these affected PLCs should implement immediate mitigations including network segmentation to isolate industrial control systems from general corporate networks, implementing web application firewalls to filter malicious redirection attempts, and conducting comprehensive security assessments of all web interfaces. The vulnerability also highlights the importance of secure coding practices and input validation as outlined in CWE-601, which specifically addresses URL redirection vulnerabilities. Security teams should establish monitoring protocols to detect unusual redirection patterns and implement user awareness training to reduce the risk of successful social engineering attacks. Additionally, manufacturers should provide firmware updates to address the root cause of the vulnerability, and organizations should maintain current vulnerability management processes to ensure timely remediation of similar issues across their industrial control system portfolios.