CVE-2018-7788 in Modicon Quantum
Summary
by MITRE
A CWE-255 Credentials Management vulnerability exists in Modicon Quantum with firmware versions prior to V2.40. which could cause a Denial Of Service when using a Telnet connection.
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Analysis
by VulDB Data Team • 09/23/2023
The vulnerability identified as CVE-2018-7788 represents a critical credentials management flaw within Modicon Quantum programmable logic controllers that affects firmware versions prior to V2.40. This issue falls under CWE-255 which specifically addresses weaknesses in credential management systems where the system fails to properly handle authentication credentials. The vulnerability manifests through Telnet connections, which are commonly used for remote administration and monitoring of industrial control systems. The Modicon Quantum series is widely deployed in industrial environments where reliable and secure remote access is essential for system maintenance and operational oversight.
The technical flaw stems from improper handling of authentication credentials within the Telnet service implementation of these controllers. When a Telnet connection is established, the system fails to properly validate or manage the authentication process, creating a potential pathway for unauthorized access or system disruption. This credential management weakness allows attackers to exploit the Telnet service in ways that can lead to service interruption. The vulnerability specifically impacts the authentication mechanism that governs Telnet connections, which are often used for administrative tasks in industrial control environments where these devices operate.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it creates significant risks for industrial control system security. When a denial of service occurs through Telnet connections, operators lose the ability to remotely access and manage the controller, potentially leading to extended downtime for critical industrial processes. The vulnerability particularly affects environments where remote maintenance and monitoring are essential, as the Telnet service provides a standard method for system administrators to access and configure these devices. This disruption can have cascading effects on production operations, especially in scenarios where immediate access is required for troubleshooting or configuration changes.
Mitigation strategies for CVE-2018-7788 should prioritize firmware updates to version V2.40 or later, which addresses the credential management weaknesses in the Telnet implementation. Organizations should also implement network segmentation to isolate industrial control systems from general network access, reducing the attack surface for Telnet-based exploits. The use of more secure remote access methods such as SSH instead of Telnet should be enforced across industrial environments, as SSH provides better credential management and encryption capabilities. Additionally, implementing strict access controls and monitoring for Telnet connections can help detect unauthorized access attempts. This vulnerability aligns with ATT&CK techniques related to credential access and privilege escalation, making it particularly concerning for industrial cybersecurity defenses that must protect against both external and internal threats.