CVE-2017-6873 in OZW672
Summary
by MITRE
A vulnerability was discovered in Siemens OZW672 (all versions) and OZW772 (all versions) that could allow an attacker to read and manipulate data in TLS sessions while performing a man-in-the-middle (MITM) attack on the integrated web server on port 443/tcp.
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Analysis
by VulDB Data Team • 12/15/2022
The vulnerability identified as CVE-2017-6873 represents a critical security flaw in Siemens industrial devices, specifically the OZW672 and OZW772 models, which are part of the company's secure communication gateway product line. These devices are designed to provide secure network connectivity and communication between industrial control systems and enterprise networks, making them critical components in industrial automation environments. The vulnerability manifests in the device's handling of Transport Layer Security (TLS) sessions, which are fundamental to establishing secure communications over network protocols. The affected devices operate an integrated web server on port 443/tcp, which serves as the primary interface for configuration and management activities, making this attack vector particularly dangerous for industrial control environments.
The technical flaw stems from improper implementation of TLS session handling mechanisms within the Siemens devices, creating a vulnerability that allows attackers to perform man-in-the-middle attacks without requiring authentication or prior access to the network. This weakness specifically affects the TLS protocol implementation during session establishment and data transmission phases, enabling attackers to intercept, read, and manipulate data flowing through TLS connections. The vulnerability's impact is amplified by the fact that it operates at the transport layer security level, meaning that even if network traffic is encrypted, the integrity and confidentiality of communications can be compromised. The flaw essentially allows an attacker positioned between the device and its communicating peers to decrypt and modify data, potentially leading to unauthorized control of industrial processes or theft of sensitive operational information.
The operational impact of this vulnerability extends beyond simple data theft, as it fundamentally undermines the security posture of industrial networks that rely on these devices for secure communications. In industrial control systems, the ability to manipulate TLS sessions can lead to unauthorized access to control commands, modification of operational parameters, or complete compromise of process control functions. The vulnerability affects devices deployed in critical infrastructure sectors including energy, water treatment, manufacturing, and other industrial environments where operational technology (OT) systems are connected to corporate networks. Attackers could potentially use this vulnerability to disrupt operations, cause physical damage to equipment, or gain access to sensitive operational data that could be used for further attacks on the broader industrial network infrastructure.
Organizations should implement immediate mitigations including network segmentation to isolate affected devices, deployment of network monitoring solutions to detect anomalous TLS traffic patterns, and implementation of additional authentication mechanisms beyond what the device provides. The vulnerability aligns with CWE-310, which addresses cryptographic weaknesses in security implementations, and represents a significant risk under the ATT&CK framework's T1071.004 technique for application layer protocol traffic shaping. Security professionals should also consider implementing certificate pinning mechanisms, regular network vulnerability assessments, and ensuring that all industrial devices are running the latest firmware versions provided by Siemens. Additionally, organizations should conduct thorough security audits of their OT environments to identify other potentially vulnerable devices that may share similar cryptographic implementation flaws, as this vulnerability demonstrates a broader pattern of inadequate security implementation in industrial communication devices that requires comprehensive remediation strategies.