CVE-2019-9744 in FL NAT SMCS 8TX
Summary
by MITRE
An issue was discovered on PHOENIX CONTACT FL NAT SMCS 8TX, FL NAT SMN 8TX, FL NAT SMN 8TX-M, and FL NAT SMN 8TX-M-DMG devices. There is unauthorized access to the WEB-UI by attackers arriving from the same source IP address as an authenticated user, because this IP address is used as a session identifier.
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Analysis
by VulDB Data Team • 08/08/2023
This vulnerability affects PHOENIX CONTACT industrial networking devices including the FL NAT SMCS 8TX, FL NAT SMN 8TX, FL NAT SMN 8TX-M, and FL NAT SMN 8TX-M-DMG models. The security flaw stems from a critical session management weakness where the system incorrectly uses the source IP address as the primary session identifier. This design decision creates a fundamental flaw in the authentication mechanism that allows unauthorized access to the web-based user interface. The vulnerability specifically impacts devices that operate in industrial environments where network segmentation and access control are paramount for operational technology security.
The technical implementation of this vulnerability violates established security principles by relying on source IP addresses for session identification rather than implementing proper authentication tokens or session management protocols. When an authenticated user establishes a connection to the device web interface, the system associates their session with their source IP address. This approach creates a dangerous scenario where any attacker who can establish a connection from the same IP address as an authenticated user can seamlessly take over that session without providing valid credentials. The flaw essentially eliminates the need for proper authentication mechanisms since IP address spoofing or network position manipulation can bypass access controls entirely.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential compromise of industrial control systems and operational technology environments. Attackers could exploit this weakness to gain administrative access to network devices that control critical infrastructure operations, potentially leading to disruption of industrial processes, data manipulation, or unauthorized configuration changes. The vulnerability is particularly concerning in industrial settings where these devices may be part of critical control networks, as it allows attackers to move laterally within the network without requiring additional credentials or complex attack vectors. This type of vulnerability directly aligns with attack patterns described in the MITRE ATT&CK framework under the credential access and privilege escalation domains.
The root cause of this vulnerability can be classified as a weakness in session management according to CWE-613, which specifically addresses inadequate session management that can lead to session fixation or session hijacking scenarios. This weakness represents a fundamental failure in implementing proper session handling mechanisms that should include unique, unpredictable session identifiers that are not derived from network attributes that can be easily replicated or manipulated. The vulnerability also relates to CWE-305, which addresses authentication mechanisms that are insufficient or improperly implemented, as the system fails to properly verify user identity through traditional authentication methods. Organizations using these devices face significant risk of unauthorized access to critical network infrastructure, potentially leading to operational disruptions or security breaches that could affect industrial control systems.
Mitigation strategies should focus on implementing proper session management protocols that use cryptographically secure session identifiers rather than IP address-based session tracking. Network administrators should consider implementing additional access controls including network segmentation, firewall rules, and multi-factor authentication mechanisms to reduce the attack surface. The device firmware should be updated to address this vulnerability through proper session management implementation that does not rely on source IP addresses for authentication purposes. Organizations should also implement network monitoring to detect unusual access patterns and consider implementing intrusion detection systems that can identify potential session hijacking attempts. Additionally, regular security assessments should be conducted to identify similar session management weaknesses in other industrial network devices and systems.