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IEC TR 62541-2
Edition 3.0 2020-11
TECHNICAL
REPORT
colour
inside
OPC unified architecture –
Part 2: Security Model
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IEC TR 62541-2
Edition 3.0 2020-11
TECHNICAL
REPORT
colour
inside
OPC unified architecture –
Part 2: Security Model
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.01 ISBN 978-2-8322-9077-4
– 2 – IEC TR 62541-2:2020 © IEC 2020
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 13
4 OPC UA security architecture . 13
4.1 OPC UA security environment . 13
4.2 Security objectives . 14
4.2.1 Overview . 14
4.2.2 Authentication. 15
4.2.3 Authorization . 15
4.2.4 Confidentiality . 15
4.2.5 Integrity . 15
4.2.6 Non-Repudiation . 15
4.2.7 Auditability . 15
4.2.8 Availability . 15
4.3 Security threats to OPC UA systems . 15
4.3.1 Overview . 15
4.3.2 Denial of Service . 16
4.3.3 Eavesdropping . 17
4.3.4 Message spoofing . 17
4.3.5 Message alteration . 17
4.3.6 Message replay . 17
4.3.7 Malformed Messages . 18
4.3.8 Server profiling . 18
4.3.9 Session hijacking . 18
4.3.10 Rogue Server . 18
4.3.11 Rogue Publisher . 18
4.3.12 Compromising user credentials . 19
4.3.13 Repudiation . 19
4.4 OPC UA relationship to site security . 19
4.5 OPC UA security architecture . 20
4.5.1 Overview . 20
4.5.2 Client / Server . 21
4.5.3 Publish-Subscribe . 22
4.6 SecurityPolicies . 23
4.7 Security Profiles . 24
4.8 Security Mode Settings . 24
4.9 User Authentication . 24
4.10 Application Authentication . 24
4.11 User Authorization . 25
4.12 Roles . 25
4.13 OPC UA security related Services . 25
4.14 Auditing . 26
4.14.1 General . 26
4.14.2 Single Client and Server . 27
4.14.3 Aggregating Server . 28
4.14.4 Aggregation through a non-auditing Server . 28
4.14.5 Aggregating Server with service distribution . 29
5 Security reconciliation . 30
5.1 Reconciliation of threats with OPC UA security mechanisms . 30
5.1.1 Overview . 30
5.1.2 Denial of Service . 31
5.1.3 Eavesdropping . 32
5.1.4 Message spoofing . 32
5.1.5 Message alteration . 33
5.1.6 Message replay . 33
5.1.7 Malformed Messages . 33
5.1.8 Server profiling . 33
5.1.9 Session hijacking . 33
5.1.10 Rogue Server or Publisher . 34
5.1.11 Compromising user credentials . 34
5.1.12 Repudiation . 34
5.2 Reconciliation of objectives with OPC UA security mechanisms . 34
5.2.1 Overview . 34
5.2.2 Application Authentication . 34
5.2.3 User Authentication . 35
5.2.4 Authorization . 35
5.2.5 Confidentiality . 35
5.2.6 Integrity . 35
5.2.7 Auditability . 35
5.2.8 Availability . 36
6 Implementation and deployment considerations . 36
6.1 Overview. 36
6.2 Appropriate timeouts . 36
6.3 Strict Message processing . 36
6.4 Random number generation . 37
6.5 Special and reserved packets . 37
6.6 Rate limiting and flow control . 37
6.7 Administrative access . 37
6.8 Cryptographic Keys . 38
6.9 Alarm related guidance . 38
6.10 Program access . 38
6.11 Audit event management . 39
6.12 OAuth2, JWT and User roles . 39
6.13 HTTPs, SSL/TLS & Websockets . 39
6.14 Reverse Connect . 39
7 Unsecured Services . 40
7.1 Overview. 40
7.2 Multicast Discovery . 40
7.3 Global Discovery Server Security . 40
7.3.1 Overview . 40
7.3.2 Rogue GDS . 40
7.3.3 Threats against a GDS . 41
– 4 – IEC TR 62541-2:2020 © IEC 2020
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