Siemens

What is Siemens?

Siemens is a German technology group, founded in Berlin in 1847 and headquartered in Munich, that is one of the world’s largest suppliers of industrial automation through its SIMATIC family of PLCs, the TIA Portal engineering software, the WinCC SCADA package and the PCS 7 DCS. Within OT, Siemens supplies PLCs, SCADA, industrial networks, drives, motion control, safety systems and industrial software. The company is also active in energy infrastructure, building management, rail and digital production environments. Because so many factories, water utilities and energy installations run on Siemens technology, the brand plays a central role in Industry 4.0 and OT convergence, and in securing them.

🏢 How is Siemens organised?

Werner von Siemens and Johann Georg Halske founded the Telegraphen-Bauanstalt von Siemens & Halske, a workshop for telegraph equipment, in Berlin on 1 October 1847. It grew into Siemens AG, which reported revenue of EUR 78.9 billion in fiscal year 2025 (ending 30 September 2025), with around 318,000 employees.

Siemens Energy (turbines, transmission) has been an independent listed company since 2020 and is no longer a Siemens division. Through acquisitions Siemens built a large software business: UGS (2007), Mentor Graphics (2017), Altair (March 2025) and Dotmatics (July 2025).

Siemens is active in manufacturing, power plants, water management, oil and gas, building automation, critical infrastructure and data centres.

⚙️ Which OT products does Siemens supply?

The automation portfolio falls under the Totally Integrated Automation (TIA) concept, which Siemens introduced in 1996: all components share one data model, one engineering environment and the same communication.

SIMATIC controllers

SIMATIC is the main automation family. SIMATIC S5 (1979) was followed in 1994 by the S7 generation with the S7-300 and S7-400. The S7-1200 (2009) and S7-1500 (shipping since 2013) are programmed in TIA Portal. ET 200 provides distributed O. SIMATIC is used for machine control, process automation, motion control, safety and IIoT integration.

TIA Portal

TIA Portal was announced at the end of 2010 and has been the central engineering platform since 2011: PLC programming, HMI configuration, network, motion and safety engineering, and simulation in a single project. It supports the IEC 61131 languages:

PCS 7 and PCS neo

PCS 7 is Siemens’ Distributed Control System for chemicals, energy, water treatment, pharmaceuticals and oil and gas. It combines process control, alarm management, historian integration, batch control and redundancy, with an operator station based on WinCC. Its web-based successor PCS neo appeared in 2019. PCS 7 works closely with SCADA and Historian environments.

WinCC

WinCC is the HMI/SCADA platform for process visualisation, trending, alarm management, reporting and web access. It connects directly to SIMATIC PLCs, PCS 7, historians and MES. WinCC Unified is the web-based new generation.

🌐 Which networks and protocols does Siemens use?

A common misconception is that PROFINET and PROFIBUS are Siemens protocols. Siemens co-developed them, but they are open standards of PROFIBUS & PROFINET International (PI), defined in IEC 61158 and IEC 61784 and implemented by many other manufacturers.

• PROFINET - real-time Industrial Ethernet with diagnostics; the IRT (Isochronous Real-Time) variant delivers the low latency and synchronisation that motion control requires
• PROFIBUS - classic fieldbus for remote I/O, drives and the process industry (PROFIBUS PA)
• S7 Comm and S7 Comm Plus - Siemens’ own protocol on TCP port 102 between PLCs, HMIs and engineering software; the classic variant has no authentication or encryption
• OPC UA - built into the S7-1500 and WinCC for connections to MES, historians, edge computing and cloud analytics
• MQTT - via libraries and edge apps for cloud integration

🛡️ How does Safety Integrated work?

With Safety Integrated, functional safety runs on the same hardware as standard control. A fail-safe CPU (S7-1200F, S7-1500F, CPU 410 in PCS 7) executes safety logic as a Safety PLC, and PROFIsafe carries safety data over the same network. Applications include safety interlocks, emergency shutdown, safe motion control and robot safety. The solutions are designed for IEC 61508 (functional safety), IEC 61511 (process safety), ISO 13849 and IEC 62061 (machinery safety).

For motion control, Siemens supplies SINAMICS drives, SIMOTION motion controllers and SIMOTICS motors, used in robotics, CNC machines, conveyors and high-speed packaging lines.

🏭 Where does Siemens sit in the Purdue model?

Siemens supplies a product at almost every level of the Purdue model. That makes integration easy, but also increases dependence on a single vendor.

On top of this sits Siemens Xcelerator, Siemens’ open digital business platform since June 2022, consisting of a portfolio, a partner ecosystem and a marketplace. It focuses on cloud integration, API connectivity, edge analytics, Industrial AI and low-code. A key element is the digital twin: real-time OT data, historical data, simulations and engineering models used together for virtual commissioning, production simulation, asset optimisation and predictive maintenance.

🔐 Why is Siemens a cyber target?

Its huge installed base makes Siemens systems an attractive OT target. Stuxnet, discovered in June 2010, replaced a STEP 7 communication library and reprogrammed S7-300 PLCs at Iran’s Natanz enrichment plant. Typical risks are:

• Unauthorised PLC downloads via an open port 102 and disabled access protection
• Compromised engineering workstations running TIA Portal or SIMATIC Manager
• Legacy protocols and systems such as the S7-300/400, old WinCC versions and PROFIBUS gateways
• Malware, ransomware and insider threats on Windows servers

Siemens itself works in line with IEC 62443: its development process for automation products is certified to IEC 62443-4-1, and Siemens ProductCERT publishes security advisories, including as a machine-readable CSAF feed, usually on the monthly Patch Tuesday.

🔧 How do you secure a Siemens installation in practice?

An approach that works in most factories and water treatment plants:

1. Inventory every CPU, HMI and engineering workstation with its firmware and software version; TIA Portal and PRONETA can scan PROFINET devices.
2. Subscribe to the ProductCERT advisories and feed them into your vulnerability management and patch management.
3. Segment in line with network segmentation and the zones and conduits model: every production cell behind an industrial firewall, no direct IT access to port 102.
4. Harden the PLCs - set a password-protected access level on the S7-1200/1500, leave PUT/GET disabled and use secure PG/HMI communication with TLS from TIA Portal V17 onwards.
5. Secure engineering with application whitelisting, MFA and remote access through a jump server.
6. Ensure recovery with backups of projects and PLC programs, version control and logging of changes.

Dutch and European context. Since 15 August 2026 the Dutch Cybersecurity Act, which implements NIS2, requires essential and important entities to manage their OT, including Siemens installations, demonstrably. The Cyber Resilience Act obliges manufacturers such as Siemens to report actively exploited vulnerabilities from 11 September 2026 and applies in full from 11 December 2027. The S7-300 and ET 200M have been in phase-out since 1 October 2023 and since 1 October 2025 can no longer be ordered as new products; spare parts remain available until around 2033. Plan a migration to the S7-1500 in your lifecycle management of legacy systems.

🔄 How does Siemens compare with other vendors?

Benefits of Siemens are its very broad portfolio, strong industrial networks, good process and motion control, extensive safety integration and worldwide support. Limitations are vendor lock-in, complex engineering environments, high implementation complexity, licence costs, long lifecycles with compatibility issues between TIA Portal versions and complex version management. Siemens platforms do offer extensive diagnostics: device diagnostics, network monitoring, trace analysis, online debugging and firmware management.

❓ Frequently asked questions

Is PROFINET a Siemens protocol?

PROFINET is an open Industrial Ethernet standard of PROFIBUS & PROFINET International, defined in IEC 61158 and IEC 61784. Siemens co-developed PROFINET and is its largest supplier, but many other manufacturers also build PROFINET devices. Siemens’ truly proprietary protocol is S7 Comm on TCP port 102.

What is the difference between SIMATIC and TIA Portal?

SIMATIC is Siemens’ product family of PLCs, I/O, HMI panels and industrial PCs. TIA Portal is the engineering software you use to configure and program SIMATIC PLCs, HMIs, drives and networks. Older S7-300/400 projects often still run in the classic SIMATIC Manager (STEP 7 Classic).

Is the Siemens S7-300 still available?

Not as a new product: the S7-300 and ET 200M entered phase-out on 1 October 2023, and since 1 October 2025 they can no longer be ordered regularly. According to Siemens, spare parts remain available until around 2033. Its successor is the S7-1500, which is programmed in TIA Portal. Migration requires new engineering, retesting and planned downtime.

Where can you find security advisories for Siemens products?

Siemens ProductCERT publishes security advisories for vulnerabilities in Siemens products, with CVE numbers, CVSS scores and mitigations. The advisories are available as web pages, an RSS feed, a mailing list and a machine-readable CSAF feed. They are usually released on the monthly Patch Tuesday.

What is Siemens Xcelerator?

Siemens Xcelerator has been Siemens’ open digital business platform since June 2022, with a portfolio of hardware, software and services, a partner ecosystem and a marketplace. The platform connects OT products such as SIMATIC with software for digital twins, simulation and cloud analytics. Its goal is to make IT/OT integration easier.

Why did Stuxnet target Siemens?

Stuxnet targeted Siemens because Iran’s Natanz enrichment plant used S7-300 PLCs with STEP 7 to control its centrifuges. The worm replaced a STEP 7 library, silently loaded its own code into the PLCs and showed operators normal values. Stuxnet was discovered in June 2010 and is regarded as the first known cyber weapon to cause physical damage.

📌 In summary

With SIMATIC, TIA Portal, WinCC and PCS 7, Siemens is one of the world’s largest OT suppliers, with products at almost every level of the Purdue model. That broad installed base also makes Siemens systems an attractive cyber target. Segmentation, PLC hardening, following ProductCERT advisories and a timely migration away from the S7-300/400 are therefore essential.