TR 33.926 [6], clause K.2.2.1, Resynchronization

Synchronization failure handling

TS 33.501 [7], clause 6.1.3.3.2

"Upon receiving an authentication failure message with synchronisation failure (AUTS) from the UE, the SEAF sends an Nausf_UEAuthentication_Authenticate Request message with a "synchronisation failure indication" to the AUSF and the AUSF sends an Nudm_UEAuthentication_Get Request message to the UDM/ARPF, together with the following parameters:

• RAND sent to the UE in the preceding Authentication Request, and

• AUTS received by the SEAF in the response from the UE to that request, as described in clause 6.1.3.2.0 and 6.1.3.3.1.

An SEAF will not react to unsolicited "synchronisation failure indication" messages from the UE.

The SEAF does not send new authentication requests to the UE before having received the response to its Nausf_UEAuthentication_Authenticate Request message with a "synchronisation failure indication" from the AUSF (or before it is timed out). "

as specified in TS 33.501[7], clause 6.1.3.3.2.

Verify that synchronization failure is correctly handled by the SEAF/AMF.

• Test environment with UE and AUSF. The UE and the AUSF may be simulated.

• AMF network product is connected in emulated/real network environment.

Test A:

1. The UE sends an authentication failure message to the SEAF/AMF with synchronisation failure (AUTS).

2. The SEAF/AMF sends a Nausf_UEAuthentication_Authenticate Request message with a "synchronisation failure indication" to the AUSF.

3. The AUSF sends a Nausf_UEAuthentication_Authenticate Response message to the SEAF/AMF immediately after receiving the request from the SEAF/AMF, to make sure the SEAF/AMF will receive the response before timeout.

Test B:

1. The UE sends an authentication failure message to the SEAF/AMF with synchronisation failure (AUTS).

2. The SEAF/AMF sends a Nausf_UEAuthentication_Authenticate Request message with a "synchronisation failure indication" to the AUSF.

3. The AUSF does not send a Nausf_UEAuthentication_Authenticate Response message to the SEAF/AMF before timeout.

Before receiving Nausf_UEAuthentication_Authenticate Response message from the AUSF and before the timer for receiving Nausf_UEAuthentication_Authenticate Response message runs out,

For Test B, the SEAF/AMF does not send any new authentication request to the UE.

For Test A, the SEAF/AMF may initiate new authentication towards the UE.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

TR 33.926 [6], clause K.2.2.1, Resynchronization

Synchronization failure handling

• RAND sent to the UE in the preceding Authentication Request, and

• AUTS received by the SEAF in the response from the UE to that request, as described in clause 6.1.3.2.0 and 6.1.3.3.1 of TS 33.501 [2].

An SEAF will not react to unsolicited "synchronisation failure indication" messages from the UE.

Verify that synchronization failure is correctly handled by the SEAF/AMF.

• Test environment with UE and AUSF. The UE and the AUSF may be simulated.

• AMF network product is connected in emulated/real network environment.

Test A:

1. The tester triggers the UE to perform a registration procedure up until the point where the UE receives a NAS Authentication Request message from the network.

2. The tester configures the UE to send an Authentication Failure message to the SEAF/AMF with synchronisation failure (AUTS), after receiving the NAS authentication request message.

3. Immediately after sending the Authentication Failure message, the UE starts timer T3520 as specified in section 5.4.1.3.7 of TS 24.501 [5].

4. The SEAF/AMF sends a Nausf_UEAuthentication_Authenticate Request message with a "synchronisation failure indication" to the AUSF.

5. The AUSF sends a Nausf_UEAuthentication_Authenticate Response message to the SEAF/AMF immediately after receiving the request from the SEAF/AMF, to make sure the SEAF/AMF will receive the response before timeout of T3520.

Test B:

1. The tester triggers the UE to perform a registration procedure up until the point where the UE receives a NAS Authentication Request message from the network.

2. The tester configures the UE to send an Authentication Failure message to the SEAF/AMF with synchronisation failure (AUTS), after receiving the NAS Authentication Request message.

3. Immediately after sending the Authentication Failure message, the UE starts timer T3520 as specified in section 5.4.1.3.7 of TS 24.501 [5].

4. The SEAF/AMF sends a Nausf_UEAuthentication_Authenticate Request message with a "synchronisation failure indication" to the AUSF.

5. The tester configures the AUSF in a way, that it does not send a Nausf_UEAuthentication_Authenticate Response message to the SEAF/AMF before timeout of T3520.

TR 33.926 [6], clause K.2.2.3, RES* verification failure

RES* verification failure handling

TS 33.501 [7], clause 6.1.3.2.2

"The SEAF shall proceed with step 10 in Figure 6.1.3.2-1 and after receiving the Nausf_UEAuthentication_Authenticate Request message from the AUSF in step 12 in Figure 6.1.3.2-1, proceed as described below:

• If the AUSF has indicated in the Nausf_UEAuthentication_Authenticate Response message to the SEAF that the verification of the RES* was not successful in the AUSF, or

• if the verification of the RES* was not successful in the SEAF,

then the SEAF shall either reject the authentication by sending an Authentication Reject to the UE if the SUCI was used by the UE in the initial NAS message or the SEAF/AMF shall initiate an Identification procedure with the UE if the 5G-GUTI was used by the UE in the initial NAS message to retrieve the SUCI and an additional authentication attempt may be initiated.

Also, if the SEAF does not receive any Nausf_UEAuthentication_Authenticate Request message from the AUSF as expected, then the SEAF shall either reject the authentication to the UE or initiate an Identification procedure with the UE."

As specified in TS 33.501 [7], clause 6.1.3.2.2.

1. Verify that the SEAF/AMF correctly handles RES* verification failure detected in the SEAF/AMF or/and in the AUSF, when the SUCI is included in the initial NAS message.

2. Verify that the SEAF/AMF correctly handles RES* verification failure detected in the SEAF/AMF or/and in the AUSF, when the 5G-GUTI is included in the initial NAS message.

Test environment with UE and AUSF. The UE and the AUSF may be simulated.

A. Test Case 1

1. The UE sends RR with SUCI to the SEAF/AMF under test, to trigger the SEAF/AMF under test to initiate the authentication, i.e. to send Nausf_UEAuthentication_Authenticate Request to the AUSF.

2. The AUSF, after receiving the request from the SEAF/AMF under test, responds with a Nausf_UEAuthentication_Authenticate Response message with an authentication vector to the SEAF/AMF under test.

3. The UE, after receiving the Authentication Request message from the SEAF/AMF under test, returns an incorrect RES\ to the SEAF/AMF under test in the NAS Authentication Response message, which will trigger the AMF to compute HRES\, compare HRES\ with HXRES\ and send an authentication request to the AUSF. The tester captures the value of RES* in the request.

4. The AUSF returns to the AMF under test the indication of RES* verification failure.

B. Test Case 2

1. The UE sends RR with a 5G-GUTI to the SEAF/AMF under test, to trigger the SEAF/AMF under test to initiate the authentication, i.e. to send Nausf_UEAuthentication_Authenticate Request to the AUSF.

2. The AUSF, after receiving the request from the SEAF/AMF under test, responds with a Nausf_UEAuthentication_Authenticate Response message with an authentication vector to the SEAF/AMF under test.

3. The UE, after receiving the Authentication Request message from the SEAF/AMF under test, returns an incorrect RES\ to the SEAF/AMF in the NAS Authentication Response message, which will trigger the AMF to compute HRES\ and compare HRES\ with HXRES\, and send an authentication request to the AUSF. The tester captures the value of RES* in the request.

4. The AUSF returns to the AMF under test an indication of RES* verification failure.

C. Test Case 3

1. The UE sends RR with SUCI to the SEAF/AMF under test, to trigger the SEAF/AMF under test to initiate the authentication, i.e. to send Nausf_UEAuthentication_Authenticate Request to the AUSF.

2. The AUSF, after receiving the request from the SEAF/AMF under test, responds with a Nausf_UEAuthentication_Authenticate Response message with an authentication vector to the SEAF/AMF under test.

3. The UE returns RES\ to the SEAF/AMF under test in the NAS Authentication Response message, which will trigger the AMF to compute HRES\, compare HRES\ with HXRES\, and send to the received RES* to the AUSF.

4. The AUSF returns to the AMF under test an indication of RES* verification failure.

D Test Case 4

1. The UE sends RR with 5G-GUTI to the SEAF/AMF under test, to trigger the SEAF/AMF under test to initiate the authentication, i.e. to send Nausf_UEAuthentication_Authenticate Request to the AUSF.

2. The AUSF, after receiving the request from the SEAF/AMF under test, responds with a Nausf_UEAuthentication_Authenticate Response message with an authentication vector to the SEAF/AMF under test.

3. The UE returns RES\ to the SEAF/AMF under test in the NAS Authentication Response message, which will trigger the AMF to compute HRES\, compare HRES\ with HXRES\, and send to the received RES* to the AUSF.

4. The AUSF returns to the AMF under test an indication of RES* verification failure.

For test case 1 and 3, the SEAF/AMF rejects the authentication by sending an Authentication Reject to the UE.

For test case 2 and 4, the SEAF/AMF initiates an Identification procedure with the UE to retrieve the SUCI.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

TR 33.926 [6], clause K.2.2.3, RES* verification failure

RES* verification failure handling

• If the AUSF has indicated in the Nausf_UEAuthentication_Authenticate Response message to the SEAF that the verification of the RES* was not successful in the AUSF, or

• if the verification of the RES* was not successful in the SEAF,

1. Verify that the SEAF/AMF correctly handles RES* verification failure detected in the SEAF/AMF or/and in the AUSF, when the SUCI is included in the initial NAS message.

2. Verify that the SEAF/AMF correctly handles RES* verification failure detected in the SEAF/AMF or/and in the AUSF, when the 5G-GUTI is included in the initial NAS message.

Verify that the SEAF/AMF correctly handles a missing Nausf_UEAuthentication_Authenticate Response message from the AUSF.

Test environment with UE and AUSF. The UE and the AUSF may be simulated.

1. The tester triggers the UE to send a Registration Request with SUCI to the SEAF/AMF under test, to trigger the SEAF/AMF under test to initiate the authentication, i.e. to send Nausf_UEAuthentication_Authenticate Request to the AUSF.

2. The AUSF, after receiving the request from the SEAF/AMF under test, responds with a Nausf_UEAuthentication_Authenticate Response message with an authentication vector to the SEAF/AMF under test.

3. The UE, after receiving the Authentication Request message from the SEAF/AMF under test, returns an incorrect RES\ (prepared by the tester) to the SEAF/AMF under test in the NAS Authentication Response message, which will trigger the AMF to compute HRES\, compare HRES\ with HXRES\ and send an authentication request to the AUSF. The tester captures the value of RES* in the request.

4. The AUSF returns the indication of RES* verification failure to the AMF under test.

1. The tester triggers the UE to send a Registration Request with a 5G-GUTI to the SEAF/AMF under test, to trigger the SEAF/AMF under test to initiate the authentication, i.e. to send Nausf_UEAuthentication_Authenticate Request to the AUSF.

2. The AUSF, after receiving the request from the SEAF/AMF under test, responds with a Nausf_UEAuthentication_Authenticate Response message with an authentication vector to the SEAF/AMF under test.

3. The UE, after receiving the Authentication Request message from the SEAF/AMF under test, returns an incorrect RES\ (prepared by the tester) to the SEAF/AMF in the NAS Authentication Response message, which will trigger the AMF to compute HRES\ and compare HRES\ with HXRES\, and send an authentication request to the AUSF. The tester captures the value of RES* in the request.

4. The AUSF returns an indication of RES* verification failure to the AMF under test.

1. The tester triggers the UE to send a Registration Request with SUCI to the SEAF/AMF under test, to trigger the SEAF/AMF under test to initiate the authentication, i.e. to send Nausf_UEAuthentication_Authenticate Request to the AUSF.

2. The AUSF, after receiving the request from the SEAF/AMF under test, responds with a Nausf_UEAuthentication_Authenticate Response message with an authentication vector to the SEAF/AMF under test.

3. The UE returns RES\ to the SEAF/AMF under test in the NAS Authentication Response message, which will trigger the AMF to compute HRES\, compare HRES\ with HXRES\, and send to the received RES* to the AUSF.

4. The tester prepares the AUSF or intercepts and modifies its Nausf_UEAuthentication_Authenticate Response message to the SEAF/AMF to indicate that the RES* verification was not successful in the AUSF.

1. The tester triggers the UE to send a Registration Request with 5G-GUTI to the SEAF/AMF under test, to trigger the SEAF/AMF under test to initiate the authentication, i.e. to send Nausf_UEAuthentication_Authenticate Request to the AUSF.

2. The AUSF, after receiving the request from the SEAF/AMF under test, responds with a Nausf_UEAuthentication_Authenticate Response message with an authentication vector to the SEAF/AMF under test.

3. The UE returns RES\ to the SEAF/AMF under test in the NAS Authentication Response message, which will trigger the AMF to compute HRES\, compare HRES\ with HXRES\, and send to the received RES* to the AUSF.

4. The tester prepares the AUSF or intercepts and modifies its Nausf_UEAuthentication_Authenticate Response message to the SEAF/AMF to indicate that the RES* verification was not successful in the AUSF.

TBD

NAS based redirection from 5GS to EPS

TS 33.501 [7], clause 6.16.4. , TS 23.501 [8], clause 5.31.3.

"When a UE initiates registration procedure with the AMF, the AMF may redirect the UE from 5GC to EPC by including a EMM cause indicating to the UE that it shall not use 5GC, as described in clause 5.31.3 in TS 23.501 [2]. The following requirements apply to Registration Reject message with an EMM cause which indicates to the UE that the UE shall not use 5GC:

• the AMF shall only send such a Registration Reject message once NAS security has been established between the AMF and the UE; and

• the UE shall only act upon such Registration Reject message if received integrity protected and if UE has verified the integrity of the Registration Reject message successfully.

NOTE 1: This solution does not apply to unauthenticated emergency calls.

" as specified in TS 33.501 [7], clause 6.16.4. "

"In networks that support CIoT features in both EPC and 5GC, the operator may steer UEs from a specific CN type due to operator policy, e.g. due to roaming agreements, Preferred and Supported Network Behaviour, load redistribution, etc. Operator policies in EPC and 5GC are assumed to avoid steering UEs back and forth between EPC and 5GC.

" as specified in TS 23.501 [8], clause 5.31.3".

Verify that AMF under test does not send a Registration Reject message containing an EMM cause indicating to the UE that the UE shall not use 5GC , if NAS security is not established. .

NOTE 2: This test case only applies to the AMF under test which supports the security handling in CIoT.

• Test environment with UE. The UE may be simulated.

• AMF under test is connected in emulated/real network environment.

• Tester configures the operator policy of the AMF that all the UEs sending initial registration request should be redirected from 5GS to EPS.

1. UE initiates initial registration procedure with the AMF.

2. The AMF under test determines that the UE shall not use 5GC, and needs to redirect the UE from 5GC to EPC.

3. The AMF under test sends a Registration Reject message with a 5GMM cause indicating to the UE that the UE shall not use 5GC.

The NAS SMC is performed before sending the Registration Reject message.

Screenshot containing the operational results.

NAS based redirection from 5GS to EPS

• the AMF only sends such a Registration Reject message once NAS security has been established between the AMF and the UE; and

• the UE only acts upon such Registration Reject message if received integrity protected and if UE has verified the integrity of the Registration Reject message successfully.

NOTE 1: Void

NOTE 2: Void

• AMF under test supports the security handling in CIoT.

• Test environment with a CIoT UE. The UE may be simulated.

• AMF under test is connected in emulated/real network environment.

• Tester configures the operator policy of the AMF that all the UEs sending initial registration request should be redirected from 5GS to EPS.

1. The tester triggers the UE to initiate an initial registration procedure with the AMF.

2. The AMF under test determines that the UE shall not use 5GC and needs to redirect the UE from 5GC to EPC.

3. The AMF under test sends a Registration Reject message with a 5GMM cause indicating to the UE that the UE shall not use 5GC.

The NAS SMC is performed before sending the Registration Reject message.

TR 33.926 [6], clause K.2.2.2, Failed Integrity check of Initial Registration message

NAS integrity failure

TS 33.501 [2] clause 6.4.3.3.

In case of failed integrity check (i.e. faulty or missing NAS-MAC) is detected after the start of NAS integrity protection, the concerned message shall be discarded except for some NAS messages specified in TS 24.501.

Verify that AMF under test drops messages in case the NAS integrity fails or is missing.

• Test environment with UE. The UE may be simulated.

• AMF under test is connected in emulated/real network environment.

• NAS Integrity algorithm different than NIA0 is used.

Test case 1 (wrong NAS-MAC):

1. The tester triggers the UE to initiate an initial registration procedure with the AMF.

2. The AMF sends the Security Mode Complete message to the UE.

3. After the Security Mode Complete message, send a NAS message from the UE to the AMF with a wrong NAS-MAC. The message used shall not be an exception in TS 24.501 [5].

Test case 2 (missing NAS-MAC):

1. The tester triggers the UE to initiate an initial registration procedure with the AMF.

2. The AMF sends the Security Mode Complete message to the UE.

3. After the Security Mode Complete message, send a NAS message from the UE to the AMF removing the NAS-MAC field. The message used shall not be an exception in TS 24.501 [5].

In both test cases, the AMF discards the NAS messages.

Evidence suitable for the interface, e.g., Screenshot, packet captures or application log files containing the operational results.

TR 33.926 [6], clause K.2.3.1, Bidding Down

Replay protection of NAS signalling messages

TS 33.501 [7], clause 5.5.2.

" The AMF shall support integrity protection and replay protection of NAS-signalling." as specified in TS 33.501 [2], clause 5.5.2.

Verify that the NAS signalling messages are replay protected by AMF over N1 interface between UE and AMF.

• AMF network product is connected in emulated/real network environment.

• Tester shall have access to the NAS signalling packets sent between UE and AMF over N1 interface.

• Tester shall ensure that integrity protection algorithm other than NIA0 is used.

1. The tester shall capture the NAS SMC procedure taking place between UE and AMF over N1 interface using any network analyser.

2. The tester shall filter the NAS Security Mode Complete message by using a filter.

3. The tester shall check for the NAS SQN of filtered NAS Security Mode Complete message and using any packet crafting tool the tester shall create a NAS Security Mode Complete message containing same NAS SQN of the filtered NAS Security Mode Complete message or the tester shall replay the captured NAS signalling packets.

4. Tester shall check whether the replayed NAS signalling packets were processed by the AMF by capturing over N1interface to see if any corresponding response message is received from the AMF.

5. Tester shall confirm that AMF provides replay protection by dropping/ignoring the replayed packet if no corresponding response is sent by the AMF to the replayed packet.

6. Tester shall verify from the result that if the crafted NAS Security Mode Complete message or replayed NAS signalling messages are not processed by the AMF when the N1 interface is replay protected

The NAS signalling messages sent between UE and AMF over N1 interface are replay protected.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

TR 33.926 [6], clause K.2.3.1, Bidding Down

Replay protection of NAS signalling messages

Verify that the NAS signalling messages are replay protected by AMF over N1 interface between UE and AMF.

• AMF network product is connected in emulated/real network environment.

• Tester shall have access to the NAS signalling packets sent between UE and AMF over N1 interface.

• Tester shall ensure that integrity protection algorithm other than NIA0 is used.

1. The tester shall capture the NAS Security Mode Command procedure taking place between UE and AMF over N1 interface using any network analyser.

2. The tester shall filter the NAS Security Mode Complete message by using a filter.

3. The tester shall replay the captured NAS Security Mode Complete message.

4. The tester shall check whether the replayed NAS Security Mode Complete message was not processed by the AMF by capturing traffic over the N1 interface to see if no corresponding response message was sent by the AMF. If applicable, AMF application logs could be checked for the rejection of the replayed NAS Security Mode Complete message.

TR 33.926 [6], clause K.2.3.3, NAS NULL integrity protection

NAS NULL integrity protection

TS 33.501 [7], clause 5.5.2

"NIA0 shall be disabled in AMF in the deployments where support of unauthenticated emergency session is not a regulatory requirement." as specified in TS 33.501 [7], clause 5.5.2

Verify that NAS NULL integrity protection algorithm is used correctly.

Test environment with a UE. The UE may be simulated.

The AMF under test is configured to initiate authentication for both emergency and non-emergency registrations.

Test case A:

1. The UE initiates an emergency registration.

2. The AMF derives the K~AMF~ and NAS signalling keys after successful authentication of the UE.

3. The AMF sends the NAS Security Mode Command message to the UE containing the selected NAS algorithms.

Test case B:

1. The UE initiates a non-emergency registration.

2. The AMF derives the K~AMF~ and NAS signalling keys after successful authentication of the UE.

3. The AMF sends the NAS Security Mode Command message to the UE containing the selected NAS algorithms.

In both emergency and non-emergency registrations, the UE was successfully authentication and the integrity algorithm selected by the AMF in NAS SMC message is different from NIA0.

The NAS Security Mode Command message is integrity protected by the AMF.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

TR 33.926 [6], clause K.2.3.3, NAS NULL integrity protection

NAS NULL integrity protection

Verify that NAS NULL integrity protection algorithm is used correctly.

Test environment with a UE. The UE may be simulated.

The AMF under test is configured to initiate authentication for both emergency and non-emergency registrations.

Test case A:

1. The tester triggers the UE to initiate an emergency registration.

2. The tester captures the Security Mode Command procedure and verifies, that the selected NAS integrity algorithm sent by the AMF is different from NIA0.

Test case B:

1. The tester triggers the UE to initiate a non-emergency registration.

2. The tester captures the Security Mode Command procedure and verifies, that the selected NAS integrity algorithm sent by the AMF is different from NIA0.

The NAS Security Mode Command message is integrity protected by the AMF.

TR 33.926 [6], clause K.2.3.2, NAS integrity selection and use

NAS integrity algorithm selection and use

TS 33.501 [7], clause 6.7.1

"The AMF shall then initiate a NAS security mode command procedure, and include the chosen algorithm and UE security capabilities (to detect modification of the UE security capabilities by an attacker) in the message to the UE (see sub-clause 6.7.2 of the present document). The AMF shall select the NAS algorithm which have the highest priority according to the ordered lists." as specified in TS 33.501 [7], clause 5.5.2.

Verify that the AMF selects the NAS integrity algorithm which has the highest priority according to the ordered list of supported integrity algorithms and is contained in the 5G security capabilities supported by the UE.

Verify that the selected NAS security algorithm is being used.

Test environment with a UE containing its 5G security capabilities, AUSF and UDM. The UE, AUSF and UDM may be simulated.

The list of ordered NAS integrity algorithms are configured on the AMF under test.

1. The UE sends a Registration Request with Initial Registration type to the AMF unders test.

2. The tester filters the Security Mode Command and Security Mode Complete messages.

3. The tester examines the selected integrity algorithm in the SMC against the list of ordered NAS integrity algorithm and the 5G security capabilities supported by the UE. The tester examines the MAC verification of the Security Mode Complete at the AMF under test.

The selected integrity algorithm has the highest priority according to the list of ordered NAS integrity algorithm and is contained in the UE 5G security capabilities.

The MAC verification of the Security Mode Complete message is successful.

Logs and communication flow saved in a .pcap file.

TR 33.926 [6], clause K.2.3.2, NAS integrity selection and use

NAS integrity algorithm selection and use

Verify that the AMF selects the NAS integrity algorithm which has the highest priority according to the ordered list of supported integrity algorithms and is contained in the 5G security capabilities supported by the UE.

Test environment with a UE containing its 5G security capabilities, AUSF and UDM. The UE, AUSF and UDM may be simulated.

1. The tester triggers the UE to send a Registration Request with Initial Registration type to the AMF under test.

2. The tester filters the Registration Request, Security Mode Command and Security Mode Complete messages.

3. The tester examines the selected integrity algorithm in the SMC against the list of ordered NAS integrity algorithms and the 5G security capabilities supported by the UE derived from the Registration Request.

4. The tester changes the default order of the list of ordered NAS integrity algorithms on the AMF to one other valid configuration and repeats step 1-3 once.

Logs and communication flow saved in a .pcap file.

TR 33.926 [6], clause K.2.3.1, Bidding Down

Protection of initial NAS message

TS 33.501 [2], clause 6.4.6

The UE sends the NAS Security Mode Complete message to the network in response to a NAS Security Mode Command message. The NAS Security Mode Complete message is ciphered and integrity protected. Furthermore the NAS Security Mode Complete message includes the complete initial NAS message in a NAS Container if either requested by the AMF or the UE sent the initial NAS message unprotected. The AMF uses the complete initial NAS message that is in the NAS container as the message to respond to, as stated in TS 33.501 [2], clause 6.4.6, step 4.

Verify that the AMF requests the security protected retransmission of the initial NAS message from the UE in the NAS Security Mode Complete message and does proceed with the registration procedure based on the retransmitted, protected NAS Registration Request message.

• AMF network product is connected in emulated/real network environment.

• UE does not have a 5G NAS security context

• The Tester is able to intercept and modify the NAS signalling packets sent between UE and AMF over the N1 interface.

1. The tester triggers the UE to conduct an initial registration procedure.

2. The tester intercepts the unprotected Registration Request message sent from the UE to the AMF and modifies either the Requested NSSAI or Registration Type.

3. The AMF initiates the Security Mode Command Procedure after receiving the unprotected Registration Request (initial NAS message) from the UE. The AMF sets the RINMR bit (Retransmission of the initial NAS message requested) to 1 in the Security Mode Command message sent to the UE.

4. The UE sends a Security Mode Complete message with a retransmitted and protected Registration Request message to the AMF.

5. The tester observers the AMFs consecutive behaviour.

The RINMR bit is set to 1 in the Security Mode Command message sent from the AMF to the UE.

The AMFs consecutive messages (e.g. NSSAI modified: Nnssf_NSSelection_Get or Nudm_SDM_Get; Registration Type modified: Nudm_UECM_Registration; for Emergency Registration: Nsmf_PDUSession_CreateSMContext) are based on the contents of the retransmitted and protected Registration Request message of the UE.

Evidence suitable for the interface, e.g., packet captures of the N1 interface or application log files of the AMF containing the operational results.

TR 33.926 [6], clause K.2.4.1, Bidding down on Xn-Handover

Bidding down prevention in Xn-handovers

TS 33.501 [7], clause 6.7.3.1

"In the Path-Switch message, the target gNB/ng-eNB shall send the UE's 5G security capabilities received from the source gNB/ng-eNB to the AMF. The AMF shall verify that the UE's 5G security capabilities received from the target gNB/ng-eNB are the same as the UE's 5G security capabilities that the AMF has locally stored. If there is a mismatch, the AMF shall send its locally stored 5G security capabilities of the UE to the target gNB/ng-eNB in the Path-Switch Acknowledge message. The AMF shall support logging capabilities for this event and may take additional measures, such as raising an alarm."

as specified in TS 33.501 [7], clause 6.7.3.1.

Verify that bidding down is prevented by the AMF under test in Xn handovers.

Test environment with (source and target) gNBs may be simulated.

The AMF under test is configured with the UE's security context for the UE.

The AMF under test is configured to log UE security capability mismatch.

The tester sends 5G security capabilities for the UE, different from the ones stored in the AMF, to the AMF under test using a Path-Switch message.

The tester captures the Path-Switch Acknowledge message sent by AMF under test to the target gNB, which includes the locally stored 5G security capabilities in the AMF under test for that UE.

The tester verifies that a log entry showing the capability mismatch is logged.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

TR 33.926 [6], clause K.2.4.1, Bidding down on Xn-Handover

Bidding down prevention in Xn-handovers

Verify that bidding down is prevented by the AMF under test in Xn handovers.

Test environment with (source and target) gNBs may be simulated.

The AMF under test is configured with the UE's security context for the UE.

The AMF under test is configured to log UE security capability mismatch.

The tester sends 5G security capabilities for the UE, different from the ones stored in the AMF, to the AMF under test using a Path-Switch message.

TR 33.926 [6], clause K.2.4.2, NAS integrity protection algorithm selection in AMF change

NAS protection algorithm selection in AMF change

TS 33.501 [7], clause 6.7.1.2

"If the change of the AMF at N2-Handover or mobility registration update results in the change of algorithm to be used for establishing NAS security, the target AMF shall indicate the selected algorithm to the UE as defined in Clause 6.9.2.3.3 for N2-Handover (i.e., using NAS Container) and Clause 6.9.3 for mobility registration update (i.e., using NAS SMC). The AMF shall select the NAS algorithm which has the highest priority according to the ordered lists (see sub-clause 6.7.1.1 of the present document)."

as specified in TS 33.501 [7], clause 6.7.1.2.

Verify that NAS protection algorithms are selected correctly.

Test environment with source gNB, target gNB and source AMF. Source and target gNBs and source AMF may be simulated.

Test case 1: N2-Handover

The AMF under test receives the UE security capabilities and the NAS algorithms used by the source AMF from the source AMF. The AMF under test selects the NAS algorithms which have the highest priority according to the ordered lists. The lists are configured such that the algorithms selected by the AMF under test are different from the ones received from the source AMF.

Test case 2: Mobility registration update

The AMF under test receives the UE security capabilities and the NAS algorithms used by the source AMF from the source AMF. The AMF under test selects the NAS algorithms which have the highest priority according to the ordered lists. The lists are configured such that the algorithms selected by the AMF under test are different from the ones received from the source AMF.

For Test case 1, the tester captures the NASC of the NGAP HANDOVER REQUEST message sent by the AMF under test to the gNB, which includes the chosen algorithm.

For Test case 2, the AMF under test initiates a NAS security mode command procedure and includes the chosen algorithms.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

TR 33.926 [6], clause K.2.4.2, NAS integrity protection algorithm selection in AMF change

NAS protection algorithm selection in AMF change

Verify that NAS protection algorithms are selected correctly.

Test environment with source gNB, target gNB and source AMF. Source and target gNBs and source AMF may be simulated.

Test case 1: N2-Handover

Test case 2: Mobility registration update

For Test case 2, the AMF under test initiates a NAS security mode command procedure and includes the chosen algorithms.

TR 33.926 [6], clause K.2.7.1, Failure to allocate new 5G-GUTI

5G-GUTI allocation

TS 33.501 [7], clause 6.12.3

"A new 5G-GUTI shall be sent to a UE only after a successful activation of NAS security. The 5G-GUTI is defined in TS 23.003 [19].

Upon receiving Registration Request message of type "initial registration" or "mobility registration update" from a UE, the AMF shall send a new 5G-GUTI to the UE during the registration procedure.

Upon receiving Registration Request message of type "periodic registration update" from a UE, the AMF should send a new 5G-GUTI to the UE during the registration procedure.

Upon receiving Service Request message sent by the UE in response to a Paging message, the AMF shall send a new 5G-GUTI to the UE. This new 5G-GUTI shall be sent before the current NAS signalling connection is released or the N1 NAS signalling connection is suspended.

Upon receiving an indication from the lower layers that the RRC connection has been resumed for a UE in 5GMM-IDLE mode with suspend indication in response to a Paging message, the AMF shall send a new 5G-GUTI to the UE. This new 5G-GUTI shall be sent before the current NAS signalling connection is released or the suspension of the N1 NAS signalling connection.> > NOTE 1: It is left to implementation to re-assign 5G-GUTI more frequently than in cases mentioned above, for example after a Service Request message from the UE not triggered by the network..

NOTE 2: It is left to implementation to generate 5G-GUTI containing 5G-TMSI that uniquely identifies the UE within the AMF."

as specified in TS 33.501 [7], clause 6.12.3.

Verify that a new 5G-GUTI is allocated by the AMF under test in these scenarios accordingly.

For the following test case 1, 2, and 3, the following pre-conditions apply.

Test environment with a UE. The UE may be simulated.

Tester has access to the NAS signalling packets sent over N1 interface.

Tester has the knowledge of the UE's security context used for protecting the Registration Request of type "mobility registration update" and Service Request, including the old 5G-GUTI, ngKSI, UE NR security capability, NAS security context. And the tester shall configure the UE's security context on the AMF under test.For the following test case 4, more pre-conditions are required. Both the UE and the AMF under test support UP CIoT 5GS Optimization. The UE has requested the use of UP CIoT 5GS Optimization during the registration procedure, and afterwards the UE has gone to CM Idle with Suspend Indicator.

Test case 1:

Upon receiving Registration Request message of type "initial registration" from a UE, the AMF sends a new 5G-GUTI to the UE during the registration procedure.

Test case 2:

Upon receiving Registration Request message of type "mobility registration update" from a UE, the AMF sends a new 5G-GUTI to the UE during the registration procedure.

Test case 3:

Upon receiving Service Request message sent by the UE in response to a Paging message, the AMF sends a new 5G-GUTI to the UE.

Test case 4:

The AMF under test is triggered to page the UE in CM Idle with Suspend Indicator. After paging the UE in CM-Idle with Suspend indicator, the AMF shall send a new 5G-GUTI to the UE.

NOTE 1: Test case 4 is only applicable to AMF supporting UP CIoT 5GS Optimization.

For Test case 1, 2, 3 and 4, the tester retrieves a new 5G-GUTI by accessing the NAS signalling packets sent by the AMF under test over N1 interface during registration procedure.

For Test case 1, 2, 3 and 4, the NAS message encapsulating the new 5G-GUTI is confidentiality and integrity protected by the AMF under test using the NAS security context, which is same as the UE's NAS security context.

The new 5G-GUTI is different from the old 5G-GUTI.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

TR 33.926 [6], clause K.2.7.1, Failure to allocate new 5G-GUTI

5G-GUTI allocation

Upon receiving Registration Request message of type "initial registration" or "mobility registration update" from a UE, the AMF shall send a new 5G-GUTI to the UE during the registration procedure.

Upon receiving Registration Request message of type "periodic registration update" from a UE, the AMF should send a new 5G-GUTI to the UE during the registration procedure.

NOTE 1: It is left to implementation to re-assign 5G-GUTI more frequently than in cases mentioned above, for example after a Service Request message from the UE not triggered by the network.

NOTE 2: Void

Verify that a new 5G-GUTI is allocated by the AMF under test in these scenarios accordingly.

For the following test case 1, 2, and 3, the following pre-conditions apply.

Test environment with a UE. The UE may be simulated.

Tester has access to the NAS signalling packets sent over N1 interface.

Test case 1:

Test case 2:

Test case 3:

Test case 4:

NOTE 1: Test case 4 is only applicable to AMF supporting UP CIoT 5GS Optimization.

For Test case 1, 2, 3 and 4, the tester retrieves a new 5G-GUTI by accessing the NAS signalling packets sent by the AMF under test over N1 interface during registration procedure.

For Test case 1, 2, 3 and 4, the NAS message encapsulating the new 5G-GUTI is confidentiality and integrity protected by the AMF under test using the NAS security context, which is same as the UE's NAS security context.

The new 5G-GUTI is different from the old 5G-GUTI.

TR 33.926 [6], clause K.2.6.1, Invalid or unacceptable UE security capabilities

Invalid or unacceptable UE security capabilities handling

TS 24.501 [5], clause 5.5.1.2.8

"

...

i) UE security capabilities invalid or unacceptable

If the REGISTRATION REQUEST message is received with invalid or unacceptable UE security capabilities (e.g. no 5GS encryption algorithms (all bits zero), no 5GS integrity algorithms (all bits zero), mandatory 5GS encryption algorithms not supported or mandatory 5GS integrity algorithms not supported, etc.), the AMF shall return a REGISTRATION REJECT message."

as specified in TS 24.501 [5], clause 5.5.1.2.8.

Verify that UE security capabilities invalid or unacceptable are not accepted by the AMF under test in registration procedure.

Test environment with (target) UE, which may be simulated.

The tester configures invalid/unacceptable UE security capabilities (no 5GS encryption algorithms (all bits zero), no 5GS integrity algorithms (all bits zero), mandatory 5GS encryption algorithms not supported or mandatory 5GS integrity algorithms not supported) on the UE.

The UE sends UE security capabilities to the AMF under test using registration request message.

The tester captures the Registration reject message sent by AMF under test to the UE.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

TR 33.926 [6], clause K.2.6.1, Invalid or unacceptable UE security capabilities

Invalid or unacceptable UE security capabilities handling

TS 24.501 [5], clause 5.5.1.2.8

Verify that UE security capabilities invalid or unacceptable are not accepted by the AMF under test in registration procedure.

Test environment with (target) UE, which may be simulated.

The tester configures invalid/unacceptable UE security capabilities (no 5GS encryption algorithms (all bits zero), no 5GS integrity algorithms (all bits zero), mandatory 5GS encryption algorithms not supported or mandatory 5GS integrity algorithms not supported) on the UE.

TR 33.926 [4], clause K.2.6.2 Invalid encoding of UE security capabilities on the NG interface

Correct transfer of UE security capabilities in AS security establishment

TS 33.501 [2], clause 6.7.3.0.

As specified in TS33.501 [2], clause 6.7.3.0, when AS security context is to be established in the gNB/ng-eNB, the AMF sends the UE 5G security capabilities to the gNB/ng-eNB.

Verify that the UE security capabilities sent by the UE in the initial NAS registration request are the same UE security capabilities sent in the NGAP Context Setup Request message to establish AS security.

• Test environment with UE, gNodeB, AUSF and UDM. All of them may be simulated.

• The tester configures valid UE 5G security capabilities.

• The tester captures the NGAP traffic between the gNodeB and AMF on the N2 interface.

The tester triggers the initial NAS registration procedure with valid UE security capabilities.

The NGAP Context Setup Request contains the same UE 5G security capabilities as sent in the initial NAS registration request.

• List of configured UE 5G security capabilities

• Network trace (*.pcap file) containing the captured messages.

TR 33.926 [5], clause K.2.9.1 --Failed Verification of UE Identity during RRC Reestablishment Procedure for CP CIoT 5GS Optimization.

RRCRestablishment in Control Plane CIoT 5GS Optimization

TS 38.413 [9], clause 8.3.8.2

"Upon receiving the RAN CP RELOCATION INDICATION message, the AMF shall authenticate the request using the NAS-level security information received in the UL CP Security Information IE and if the authentication is successful initiate the Connection Establishment Indication procedure including NAS-level security information in the DL CP Security Information IE.

In case the AMF cannot authenticate the UE's request, the CONNECTION ESTABLISHMENT INDICATION message does not contain security information, and the NG-RAN node shall fail the RRC Re-establishment.

In case of authentication failure, the NG-RAN node and the AMF should locally release the allocated NG resources, if any." as specified in TS 38.413 [9], clause 8.3.8.2.

To verify that the verification of RRC Reestablishment is applied correctly.

Test environment with UE and ng-eNB, which may be simulated. The UE is using Control Plane CIoT 5GS Optimization.

A. Test Case 1

1. The UE sends the RRC Connection Reestablishment Request message to the ng-eNB.

2. The ng-eNB sends RAN CP RELOCATION INDICATION message to the AMF.

B. Test Case 2

1. The UE sends the RRC Connection Reestablishment Request message to the ng-eNB.

2. The ng-eNB sends RAN CP RELOCATION INDICATION message to the AMF. The ng-eNB modifies UL NAS MAC in UL CP Security Information

For test case 1, the AMF sends CONNECTION ESTABLISHMENT INDICATION to the ng-eNB, and DL CP Security Information is included.

For test case 2, the AMF sends CONNECTION ESTABLISHMENT INDICATION to the ng-eNB, and DL CP Security Information is not included.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

TR 33.926 [5], clause K.2.9.1 --Failed Verification of UE Identity during RRC Reestablishment Procedure for CP CIoT 5GS Optimization.

RRCRestablishment in Control Plane CIoT 5GS Optimization

TS 38.413 [9], clause 8.3.8.2

"Upon receiving the RAN CP RELOCATION INDICATION message, the AMF shall authenticate the request using the NAS-level security information received in the UL CP Security Information IE and if the authentication is successful initiate the Connection Establishment Indication procedure including NAS-level security information in the DL CP Security Information IE.

In case of authentication failure, the NG-RAN node and the AMF should locally release the allocated NG resources, if any." as specified in TS 38.413 [9], clause 8.3.8.2.

To verify that the verification of RRC Reestablishment is applied correctly.

Test environment with UE and ng-eNB, which may be simulated. The UE is using Control Plane CIoT 5GS Optimization.

1. The tester triggers the UE to send the RRC Connection Reestablishment Request message to the ng-eNB.

2. The ng-eNB sends RAN CP RELOCATION INDICATION message to the AMF.

1. The tester triggers the UE to send the RRC Connection Reestablishment Request message to the ng-eNB.

2. The ng-eNB sends RAN CP RELOCATION INDICATION message to the AMF. The ng-eNB modifies UL NAS MAC in UL CP Security Information

TR 33.926 [6], clause K.2.X, Incorrect Validation of S-NSSAIs

validation of S-NSSAIs in PDU session establishment request

TS 24.501 [5], clause 5.4.5.2.5

"

13) if the Request type IE is set to "initial request" and the S-NSSAI IE contains an S-NSSAI that is not allowed by the network, then the AMF shall send back to the UE the 5GSM message which was not forwarded as specified in subclause 5.4.5.3.1 case e) or case f);" as specified in TS 24.501 [5], clause 5.4.5.2.5.

Verify that S-NSSAIs which are not within Allowed NSSAI list are not accepted by the AMF under test in PDU session establishment procedure.

Test environment with UE, UDM, SMF and NSSAAF, which may be simulated.

The tester configures UDM with an S-NSSAI that require Network Slice-Specific Authentication and Authorizationin in UE's subscription information.

A. Test Case 1

1. The UE sends the S-NSSAI that require NSSAA to the AMF under test using registration request message.

2. After receiving the NSSAA request from the AMF, the NSSAAF sends EAP success to AMF.

3. The UE sends PDU session establishment request to the AMF with the S-NSSAI.

B. Test Case 2

1. The UE sends the S-NSSAI that require NSSAA to the AMF under test using registration request message.

2. After receiving the NSSAA request from the AMF, the NSSAAF sends EAP failure to AMF.

3. The UE sends PDU session establishment request to the AMF with the S-NSSAI.

For test case 1, the AMF continues the PDU session establishment procedure by sending a Nsmf_PDUSession_CreateSMContext Request to the SMF.

For test case 2, the AMF aborts the PDU session establishment procedure by sending back the 5GSM message to the UE.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

validation of S-NSSAIs in PDU session establishment request

TS 24.501 [5], clause 5.4.5.2.5

Verify that S-NSSAIs which are not within Allowed NSSAI list are not accepted by the AMF under test in PDU session establishment procedure.

Test environment with UE, UDM, SMF and NSSAAF, which may be simulated.

The tester configures UDM with an S-NSSAI that require Network Slice-Specific Authentication and Authorizationin in UE's subscription information.

1. The tester triggers the UE to send the S-NSSAI that require NSSAA to the AMF under test using registration request message.

2. After receiving the NSSAA request from the AMF, the NSSAAF sends EAP success to AMF.

3. The UE sends PDU session establishment request to the AMF with the S-NSSAI.

1. The tester triggers the UE to send the S-NSSAI that require NSSAA to the AMF under test using registration request message.

2. After receiving the NSSAA request from the AMF, the NSSAAF sends EAP failure to AMF.

3. The UE sends PDU session establishment request to the AMF with the S-NSSAI.

TR 33.926, clause K.2.X

NSSAA revocation

TS 33.501 [7], clause 16.5

" If no S-NSSAI is left in Allowed NSSAI for an access after the revocation, and no Default NSSAI can be provided to the UE in the Allowed NSSAI or a previous NSSAA failed for the Default NSSAI over this access, then the AMF shall execute the Network-initiated Deregistration procedure for the access as described in subclause 4.2.2.3.3 in TS 23.502 [8], and it shall include in the explicit De-Registration Request message the list of Rejected S-NSSAIs, each of them with the appropriate rejection cause value. "

as specified in TS 33.501[7], clause 16.5

Verify that AMF deregisters UE when, after slice specific authorization revocation, there is no allowed NSSAI or Default NSSAI that can be used by UE.

Test environment with UE. The UE may be simulated.

The AMF under test is configured with one S-NSSAI in the Allowed NSSAI and no default S-NSSAI.

A message requesting the AMF under test to revoke the authorization of the S-NSSAI in the Allowed NSSAI is simulated and sent the AMF under test.

The Deregistration Request message is sent by the AMF under test to the UE.

Evidence suitable for the interface, e.g., Screenshot containing the operational results.

NOTE 1: This test case is only applicable to AMF supporting Network Slice Specific Authentication and Authorization.

NSSAA revocation

Verify that AMF deregisters UE when, after slice specific authorization revocation, there is no allowed NSSAI or Default NSSAI that can be used by UE.

Test environment with UE. The UE may be simulated.

The Deregistration Request message is sent by the AMF under test to the UE.

NOTE 1: Void