oSIST prEN 304 636 V1.0.0:2026

Draft ETSI EN 304 636 V1.0.0 (2026-07)

HARMONISED EUROPEAN STANDARD
Cybersecurity (CYBER);
CRA;
Cybersecurity requirements for firewalls,
intrusion detection and/or prevention systems

2 Draft ETSI EN 304 636 V1.0.0 (2026-07)

Reference
DEN/CYBER-EUS-0020
Keywords
CRA, cybersecurity, firewall
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ETSI
3 Draft ETSI EN 304 636 V1.0.0 (2026-07)
Contents
Intellectual Property Rights . 8
Foreword. 9
Modal verbs terminology . 9
Introduction . 9
1 Scope . 10
2 References . 11
2.1 Normative references . 11
2.2 Informative references . 11
3 Definition of terms, symbols and abbreviations . 13
3.1 Terms . 13
3.2 Symbols . 15
3.3 Abbreviations . 15
4 Product context . 16
4.1 Introduction. 16
4.2 Product functions . 16
4.2.1 General product functions . 16
4.2.1.1 General . 16
4.2.1.2 [FN-G-01] Configuration and management . 16
4.2.1.3 [FN-NC-01] Network connectivity . 17
4.2.1.4 [FN-LG-01] Logging . 17
4.2.1.5 [FN-TI-01] Traffic inspection and analysis . 17
4.2.1.6 [FN-SM-01] Signature and intelligence management . 17
4.2.2 Product functions implemented by firewalls and intrusion prevention systems. 17
4.2.2.1 General . 17
4.2.2.2 [FN-SP-01] Traffic access control and decision making . 17
4.2.2.3 [FN-SG-01] Traffic segmentation . 17
4.2.3 Product functions implemented by intrusion detection systems and intrusion prevention systems . 17
4.2.3.1 General . 17
4.2.3.2 [FN-TD-01] Threat detection and pattern matching . 17
4.3 Product architecture . 18
4.3.1 General . 18
4.3.2 Product assets . 18
4.3.3 Product capabilities . 18
4.4 Operational environment . 18
4.4.1 General description . 18
4.4.2 Physical environment . 18
4.4.3 Logical environment . 19
4.4.4 Connectivity aspects . 19
4.5 Distribution of security functions . 19
4.6 Users . 19
4.7 Use cases . 20
4.7.1 General . 20
4.7.2 Perimeter security deployments . 20
4.7.3 Internal segmentation deployments . 20
4.7.4 Data centre security deployments . 20
4.7.5 Cloud security deployments . 21
4.7.6 Distributed branch office protection . 21
4.7.7 Network forensics deployments . 21
4.7.8 Threat hunting deployments . 21
4.7.9 Host-based security deployments . 21
4.7.10 Application security deployments . 21
4.7.11 Managed security service deployments . 21
5 Technical requirements for the products . 22
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4 Draft ETSI EN 304 636 V1.0.0 (2026-07)
5.1 Introduction - Applicability of the requirements . 22
5.2 Appropriate level of cybersecurity . 22
5.3 No known exploitable vulnerabilities . 22
5.3.1 [KEV-1] No known exploitable vulnerabilities . 22
5.3.1.1 General . 22
5.3.1.2 Requirements . 22
5.4 Secure by default configuration . 23
5.4.1 [DEFAULT-1] Secure by default configuration . 23
5.4.1.1 General . 23
5.4.1.2 Requirements . 23
5.4.2 [RESET-1] Factory reset . 24
5.4.2.1 General . 24
5.4.2.2 Requirements . 24
5.5 Security updates . 24
5.5.1 [UPDATE-1] Update mechanisms . 24
5.5.1.1 General . 24
5.5.1.2 Requirements . 24
5.6 Authentication and access control . 25
5.6.1 [AUTH-1] Authentication . 25
5.6.1.1 General . 25
5.6.1.2 Requirements . 25
5.6.2 [AUTH-2] Authorisation . 26
5.6.2.1 General . 26
5.6.2.2 Requirements . 26
5.6.3 [AUTH-3] Authenticated session lifecycle . 26
5.6.3.1 General . 26
5.6.3.2 Requirements . 26
5.6.4 [AUTH-4] Protocol access control . 27
5.6.4.1 General . 27
5.6.4.2 Requirements . 27
5.7 Confidentiality protection . 27
5.7.1 General . 27
5.7.2 Requirements. 28
5.8 Availability protection . 28
5.8.1 General . 28
5.8.2 Requirements. 28
5.9 Non-interference . 29
5.9.1 General . 29
5.9.2 Requirements. 29
5.10 Attack surface minimalisation . 29
5.10.1 [INTEGRITY-1] System integrity and boot process . 29
5.10.1.1 General . 29
5.10.1.2 Requirements . 29
5.10.2 [PACKET-1] Default packet disposition. 30
5.10.2.1 General . 30
5.10.2.2 Requirements . 30
5.10.3 [EXPOSURE-1] Interface and service exposure minimisation . 30
5.10.3.1 General . 30
5.10.3.2 Requirements . 30
5.11 Monitoring and logging . 30
5.11.1 General . 30
5.11.2 Requirements. 30
5.12 Data management . 31
5.12.1 [TRANSFER-1] Secure data export and transfer . 31
5.12.1.1 General . 31
5.12.1.2 Requirements . 31
5.12.2 [SIGNATURE-1] Signature update and validation . 31
5.12.2.1 General . 31
5.12.2.2 Requirements . 31
5.13 Remote data processing solutions . 32
5.13.1 General . 32
5.13.2 Requirements. 32
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5 Draft ETSI EN 304 636 V1.0.0 (2026-07)
6 Assessment criteria for compliance with technical requirements . 33
6.1 Introduction to the assessment and compliance criteria . 33
6.2 Appropriate level of cybersecurity . 33
6.3 No known exploitable vulnerabilities . 33
6.3.1 [KEV-1] No known exploitable vulnerabilities . 33
6.3.1.1 Requirement assessments . 33
6.4 Secure by default configuration . 36
6.4.1 [DEFAULT-1] Secure by default configuration . 36
6.4.1.1 Requirement assessments . 36
6.4.2 [RESET-1] Factory reset . 48
6.4.2.1 Requirement assessments . 48
6.5 Security updates . 51
6.5.1 [UPDATE-1] Update mechanisms . 51
6.5.1.1 Requirement assessments . 51
6.6 Authentication and access control . 58
6.6.1 [AUTH-1] Authentication . 58
6.6.1.1 Requirement assessments . 58
6.6.2 [AUTH-2] Authorisation . 66
6.6.2.1 Requirement assessments . 66
6.6.3 [AUTH-3] Authenticated session lifecycle . 70
6.6.3.1 Requirement assessments . 70
6.6.4 [AUTH-4] Protocol access control . 74
6.6.4.1 Requirement assessments . 74
6.7 Confidentiality protection . 79
6.7.1 Requirement assessments . 79
6.8 Availability protection . 85
6.8.1 Requirement assessments . 85
6.9 Non-interference . 88
6.9.1 Requirement assessments . 88
6.10 Attack surface and mitigation . 90
6.10.1 [INTEGRITY-1] System integrity and boot process . 90
6.10.1.1 Requirement assessments . 90
6.10.2 [PACKET-1] Default packet disposition. 94
6.10.2.1 Requirement assessments . 94
6.10.3 [EXPOSURE-1] Interface and service exposure minimisation . 99
6.10.3.1 Requirement assessments . 99
6.11 Monitoring and logging . 102
6.11.1 Requirement assessments . 102
6.12 Data management . 105
6.12.1 [TRANSFER-1] Secure data export and transfer . 105
6.12.1.1 Requirement assessments . 105
6.12.2 [SIGNATURE-1] Signature update and validation . 109
6.12.2.1 Requirement assessments . 109
6.13 Remote data processing solutions . 115
6.13.1 Requirement assessments . 115
Annex A (informative): Relationship between the present document and the essential
cybersecurity requirements of EU Regulation (EU) 2024/2847 . 120
Annex B (informative): Security analysis. 122
B.1 General . 122
B.2 Threat landscape . 122
B.2.1 Threats related to vulnerability handling . 122
B.2.2 Threats related to access control and authentication . 123
B.2.3 Threats related to availability and inspection bypass . 123
B.2.4 Threats related to integrity and tampering . 124
B.2.5 Threats related to signature and intelligence integrity . 124
B.2.6 Threats related to data protection . 125
B.2.7 Threats related to monitoring and visibility . 125
B.2.8 Threats related to default configuration . 125
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6 Draft ETSI EN 304 636 V1.0.0 (2026-07)
B.2.9 Threats related to physical and deployment security . 126
B.2.10 Threats related to detection disruption . 126
B.3 Threat assessment framework . 126
B.3.1 Introduction. 126
B.3.2 Risk factors . 127
B.3.2.0 Introduction . 127
B.3.2.1 Baseline risk factors . 127
B.3.2.2 Traffic inspection risk factors. 128
B.3.2.3 Update and intelligence risk factors . 128
B.3.2.4 Deployment architecture risk factors . 128
B.3.2.5 Data operations risk factors . 128
B.3.2.6 Remote data processing risk factors . 129
B.3.3 Threat justification and mitigation . 129
Annexes C to J: Void . 133
Annex K (normative): Vertical specific state of the art cryptography . 134
K.0 General . 134
K.1 Classification of cryptographic algorithms as CRY-SOTA . 134
K.2 Assessment criteria for compliance with cryptographic requirements . 135
K.2.1 Assessment objective . 135
K.2.2 Assessment preparation . 135
K.2.3 Assessment activities . 135
K.2.4 Assessment evidence . 136
K.2.5 Assessment verdict . 137
K.3 Symmetric atomic primitives . 137
K.3.1 Block ciphers . 137
K.3.2 Stream ciphers . 138
K.3.3 Hash functions . 138
K.4 Symmetric constructions . 138
K.4.1 Confidentiality modes of operation: encryption/decryption modes . 138
K.4.2 Specific confidentiality modes: disk encryption . 138
K.4.3 Integrity modes: message authentication codes . 139
K.4.4 Symmetric entity authentication schemes . 139
K.4.5 Authenticated encryption . 139
K.4.6 Key protection . 139
K.4.7 Key derivation functions . 139
K.4.8 Password protection/password hashing mechanisms . 139
K.4.9 Key combiners . 140
K.5 Asymmetric atomic primitives . 140
K.5.1 RSA/Integer factorisation . 140
K.5.2 Discrete logarithm in finite fields . 140
K.5.3 Discrete logarithm in elliptic curves . 140
K.5.4 Learning with errors in (structured) lattices . 140
K.5.5 Hash function preimage resistance . 140
K.5.6 Other intractable problems . 140
K.6 Asymmetric constructions . 141
K.6.1 Asymmetric encryption scheme . 141
K.6.2 Digital signature . 141
K.6.3 Asymmetric entity authentication schemes . 141
K.6.4 Key establishment and key encapsulation . 141
K.7 Cryptographic protocols . 141
K.7.1 QUIC . 141
K.7.2 SNMP . 142
K.7.3 Secure device identity . 142
K.7.4 Time Protocols . 142
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7 Draft ETSI EN 304 636 V1.0.0 (2026-07)
K.8 Cryptographic industry standards . 143
K.9 Crypto agility . 143
K.9.1 Requirement . 143
K.9.2 Assessment of crypto-agility. 144
K.9.2.1 Assessment objective . 144
K.9.2.2 Assessment preparation . 144
K.9.2.3 Assessment activities. 144
K.9.2.4 Assessment evidence . 144
K.9.2.5 Assessment verdict . 145
History . 146

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8 Draft ETSI EN 304 636 V1.0.0 (2026-07)
Intellectual Property Rights
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ETSI
9 Draft ETSI EN 304 636 V1.0.0 (2026-07)
Foreword
This draft Harmonised European Standard (EN) has been produced by ETSI Technical Committee Cyber Security
(CYBER), and is now submitted for the combined Public Enquiry and Vote phase of the ETSI Standardisation Request
deliverable Approval Procedure (SRdAP).
The present document has been prepared under the Commission's standardisation request C(2025)618 final [i.3] to
provide one voluntary means of conforming to the requirements of Regulation (EU) 2024/2847 of the European
Parliament and of the Council of 23 October 2024 on horizontal cybersecurity requirements for products with digital
elements and amending Regulations (EU) No 168/2013 and (EU) 2019/1020 and Directive (EU) 2020/1828 (Cyber
Resilience Act) (CRA) [i.1].
Once the present document is cited in the Official Journal of the European Union under that Regulation, compliance
with the normative clauses of the present document given in table A.1 confers, within the limits of the scope of the
present document, a presumption of conformity with the corresponding requirements of that Regulation and associated
EFTA regulations.
Proposed national transposition dates
Date of latest announcement of this EN (doa): 3 months after ETSI publication
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 6 months after doa
Date of withdrawal of any conflicting National Standard (dow): 18 months after doa

Modal verbs terminology
In the pre
...