What is Patch Management?
Patch management is the process by which software updates, security patches and Firmware updates are systematically managed and rolled out to devices, systems and applications.
The aim: fix vulnerabilities, improve stability and protect systems against known exploits.
Patch management is essential in both IT environments (servers, workstations, applications) and OT environments (PLCs, SCADA, HMIs).
🎯 Why is patch management important?
- Closes known security gaps (e.g. from CVE databases)
- Prevents exploits by malware or attackers
- Improves system performance and stability
- Essential for compliance with NIS2, ISO 27001, IEC 62443 and BIO
- Reduces the risk of incidents and downtime
🧱 The patching process step by step
- Asset inventory (via Asset Inventory)
- Detection of available updates (OS, firmware, applications)
- Risk assessment of patches (critical, non-critical)
- Testing in a test environment (especially in OT)
- Implementation planning (change window / maintenance)
- Rollout to production
- Monitoring and logging of status and errors
- Reporting and audit trail for compliance
🔐 Patch management in OT environments
There are specific considerations in industrial networks:
| Aspect | Explanation |
|---|---|
| Legacy systems | Many PLCs or HMIs run on older OS versions without update support |
| Production continuity | Patching must not disrupt the process — requires maintenance planning |
| Vendor lock-in | Only patches from the manufacturer may be applied |
| Offline systems | Not connected to the internet — manual patch distribution required |
| Test requirements | Each patch may affect functionality, so it must be validated first |
🛠️ Tools for patch management
| IT-focused | Examples |
|---|---|
| Microsoft WSUS / SCCM | Windows systems and servers |
| ManageEngine / Ivanti | Multi-platform patch management |
| Qualys / Tenable | Detection of missing patches |
| OT-focused | Examples |
|---|---|
| Claroty / Nozomi | Vulnerability and patch status for OT assets |
| Vendor tools (Siemens, Rockwell) | OEM patches for PLC, SCADA and HMI |
✅ Benefits of good patch management
- Prevents known exploits from being abused
- Increases system stability and reliability
- Supports audits, incident response and compliance
- Makes vulnerabilities visible and manageable
- Reduces costs through fewer incidents or remediation actions
⚠️ Challenges
- Patching 24/7 production environments
- Lack of overview of assets or patch status
- Outdated equipment with no update option
- Coordination between IT, OT and suppliers
- Risk of disruption caused by poorly tested updates
📌 In summary
Patch management is the process of identifying, testing and rolling out updates to keep systems secure, stable and compliant. It is a critical building block of any cybersecurity strategy, particularly in environments with many legacy or OT systems.