CVE-2019-6576 in SIMATIC HMI Comfort Panel
Summary
by MITRE
A vulnerability has been identified in SIMATIC HMI Comfort Panels 4" - 22" (All versions < V15.1 Update 1), SIMATIC HMI Comfort Outdoor Panels 7" & 15" (All versions < V15.1 Update 1), SIMATIC HMI KTP Mobile Panels KTP400F, KTP700, KTP700F, KTP900 und KTP900F (All versions < V15.1 Update 1), SIMATIC WinCC Runtime Advanced (All versions < V15.1 Update 1), SIMATIC WinCC Runtime Professional (All versions < V15.1 Update 1), SIMATIC WinCC (TIA Portal) (All versions < V15.1 Update 1), SIMATIC HMI Classic Devices (TP/MP/OP/MP Mobile Panel) (All versions). An attacker with network access to affected devices could potentially obtain a TLS session key. If the attacker is able to observe TLS traffic between a legitimate user and the device, then the attacker could decrypt the TLS traffic. The security vulnerability could be exploited by an attacker who has network access to the web interface of the device and who is able to observe TLS traffic between legitimate users and the web interface of the affected device. The vulnerability could impact the confidentiality of the communication between the affected device and a legitimate user. At the time of advisory publication no public exploitation of the security vulnerability was known.
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Analysis
by VulDB Data Team • 06/03/2026
This vulnerability represents a critical weakness in Siemens industrial human machine interface (HMI) and runtime software products that affects multiple device families including Comfort Panels, Outdoor Panels, Mobile Panels, and WinCC products. The flaw resides in the implementation of Transport Layer Security (TLS) cryptographic protocols, specifically in how these industrial devices handle TLS session key management. According to the Common Weakness Enumeration framework, this vulnerability maps to CWE-327 which addresses broken cryptographic implementations and weak encryption algorithms. The security issue stems from insufficient protection of TLS session keys, creating an avenue for man-in-the-middle attacks that compromise the confidentiality of communications between legitimate users and affected devices.
The technical exploitation of this vulnerability requires an attacker to possess network access to the affected device's web interface and the ability to observe TLS traffic between legitimate users and the device. This attack vector aligns with ATT&CK technique T1041 for Data Compressed in Command and T1566 for Phishing, as it typically involves network-based reconnaissance and traffic interception. The vulnerability specifically impacts the confidentiality aspect of the CIA triad, potentially allowing attackers to decrypt sensitive communication channels that should remain protected. The affected products span across multiple Siemens HMI device categories, indicating a widespread exposure across industrial control systems that rely on these platforms for operational technology environments.
The operational impact of this vulnerability extends beyond simple data confidentiality concerns, as industrial control systems often handle critical infrastructure operations where communication integrity and confidentiality are paramount. Attackers exploiting this vulnerability could potentially access sensitive operational data, user credentials, or system configurations that could lead to further compromise of industrial control systems. The vulnerability affects devices running versions prior to V15.1 Update 1, suggesting that Siemens has acknowledged and addressed this weakness in their security updates. Organizations operating these affected systems face increased risk of unauthorized access to their industrial processes, potentially leading to operational disruption or safety hazards in critical infrastructure environments.
Mitigation strategies should prioritize immediate deployment of Siemens security updates and patches for all affected device versions, as these releases contain the necessary cryptographic improvements to address the TLS session key exposure. Network segmentation and access controls should be implemented to limit direct network access to these industrial devices, while monitoring solutions should be deployed to detect potential traffic interception activities. Security teams should also conduct comprehensive vulnerability assessments across their industrial control system environments to identify additional devices that may be running vulnerable software versions. The implementation of network-based intrusion detection systems and continuous monitoring of TLS traffic patterns can help detect exploitation attempts. Organizations should also review their industrial cybersecurity posture and consider implementing zero-trust network architectures that minimize the attack surface for critical industrial systems.