Methods, systems, and computer readable media for mitigating location tracking and denial of service (DoS) attacks that utilize access and mobility management function (AMF) location service

1. A method for mitigating location tracking attacks and denial of service (DoS) attacks that utilize an access and mobility management function (AMF) location service, the method comprising:

receiving, at a network function (NF), an authentication response message from a home public land mobile network (HPLMN) of a user equipment (UE), wherein the NF comprises a visited security edge protection proxy (SEPP) of the UE;

extracting, by the NF and from the authentication response message, a subscription identifier and an indicator of an authentication result for the UE;

storing, by the NF and in an AMF location service validation database, the subscription identifier and the indicator of the authentication result for the UE;

receiving, by the NF, an AMF location service message;

using, by the NF, at least one of a subscription identifier extracted from the AMF location service message and contents of the AMF location service validation database, to classify the AMF location service message as a location tracking or DoS attack; and

in response to classifying the AMF location service message as a location tracking or DoS attack, preventing the location tracking or DoS attack.

2. The method of claim 1 wherein receiving an authentication response message comprises receiving an Nausf_UEAuthentication message containing an authentication result parameter and a subscription permanent identifier (SUPI).

3. The method of claim 2 wherein storing the subscription identifier and the indicator of the authentication result includes storing the SUPI and a value of the authentication result parameter.

4. The method of claim 3 wherein using at least one of the subscription identifier extracted from the AMF location service message and contents of the AMF location service validation database to identify the AMF location service message as a location tracking or DoS attack comprises:

extracting a SUPI from the AMF location service message;

determining that a source PLMN of the AMF location service message matches a home PLMN of the SUPI extracted from the AMF location service message;

performing a lookup in the AMF location service validation database using the SUPI; and

classifying the AMF location service message as a DoS attack in response to failing to locate a record corresponding to the SUPI in the AMF location service validation database or locating a record corresponding to the SUPI in the AMF location service validation database and determining that the record includes a value of an authentication result parameter that indicates that authentication of the UE was not successful.

5. The method of claim 1 wherein using at least one of a subscription identifier from the AMF location service message and contents of the AMF location service validation database to classify the AMF location service message as a location tracking or DoS attack includes:

extracting a subscription permanent identifier (SUPI) from the AMF location service message;

identifying a home PLMN from the SUPI;

determining a source PLMN of the AMF location service message; and

classifying the AMF location service message as a location tracking attack in response to determining that the home PLMN identified from the SUPI does not match the source PLMN of the AMF location service message.

6. The method of claim 5 wherein determining a source PLMN of the AMF location service message includes determining the source PLMN from a source address or a source transport layer security (TLS) certificate of the AMF location service message.

7. The method of claim 1 wherein receiving an AMF location service message includes receiving an Namf_Location service message.

8. The method of claim 7 wherein the Namf_Location service message includes one of a ProvidePositioningInfo, an EventNotify, and a Provide Location Info service operation identifier.

9. A system for mitigating location tracking and DoS attacks

that utilize an access and mobility management function (AMF) location service, the system comprising:

a network function (NF) including at least one processor and a memory, wherein the NF comprises a visited security edge protection proxy (SEPP) of the UE;

an AMF location service validation database embodied in the memory;

an authentication results collector implemented by the at least one processor for receiving an authentication response message from a home public land mobile network (HPLMN) of a user equipment (UE), extracting, from the authentication response message, a subscription identifier and an indicator of an authentication result for the UE, and storing, by the NF and in the AMF location service validation database, the subscription identifier and the indicator of the authentication result for the UE; and

an AMF location service validator implemented by the at least one processor for receiving an AMF location service message, using at least one of a subscription identifier extracted from the AMF location service message and contents of the AMF location service validation database to classify the AMF location service message as a location tracking or DoS attack, and, in response to classifying the AMF location service message as a location tracking or DoS attack, preventing the location tracking attack.

10. The system of claim 9 the authentication response message comprises an Nausf_UEAuthentication message containing an authentication result parameter and a subscription permanent identifier (SUPI).

11. The system of claim 10 wherein storing the subscription identifier comprises the SUPI and the indicator of the authentication result includes a value of the authentication result parameter.

12. The system of claim 11 wherein, in using at least one of the subscription identifier extracted from the AMF location service message and contents of the AMF location service validation database to identify the AMF location service message as a location tracking or DoS attack, the AMF location service validator is configured to:

extract a SUPI from the AMF location service message;

determine that a source PLMN of the AMF location service message matches a home PLMN of the SUPI extracted from the AMF location service message;

perform a lookup in the AMF location service validation database using the SUPI; and

classify the AMF location service message as a DoS attack in response to failing to locate a record corresponding to the SUPI in the AMF location service validation database or locating a record corresponding to the SUPI in the AMF location service validation database and determining that the record includes a value of an authentication result parameter that indicates that authentication of the UE was not successful.

13. The system of claim 9 wherein, in using at least one of a subscription identifier from the AMF location service message and contents of the AMF location service validation database to classify the AMF location service message as a location tracking or DoS attack, the AMF location service validator is configured to:

extract a subscription permanent identifier (SUPI) from the AMF location service message;

identify a home PLMN from the SUPI extracted from the AMF location service message;

determine a source PLMN of the AMF location service message; and

classify the AMF location service message as a location tracking attack in response to determining that the home PLMN identified from the SUPI does not match the source PLMN of the AMF location service message.

14. The system of claim 13 wherein the AMF location service validator is configured to determine a source PLMN of the AMF location service message by determining the source PLMN from a source address or a source transport layer security (TLS) certificate of the AMF location service message.

15. The system of claim 9 wherein the AMF location service message comprises an Namf_Location service message including one of a ProvidePositioningInfo, an EventNotify, and a ProvideLocationInfo service operation identifier.

16. A non-transitory computer readable medium having stored thereon executable instructions that when executed by a processor of a computer control the computer to perform steps comprising:

receiving, at a network function (NF), an authentication response message from a home public land mobile network (HPLMN) of a user equipment (UE), wherein the NF comprises a visited security edge protection proxy (SEPP) of the UE;

extracting, by the NF and from the authentication response message, a subscription identifier and an indicator of an authentication result for the UE;

storing, by the NF and in an access and mobility management function (AMF) location service validation database, the subscription identifier and the indicator of the authentication result for the UE;

receiving, by the NF, an AMF location service message;

using, by the NF, at least one of a subscription identifier extracted from the AMF location service message and contents of the AMF location service validation database, to classify the AMF location service message as a location tracking or denial of service (DoS) attack; and

in response to classifying the AMF location service message as a location tracking or DoS attack, preventing the location tracking or DoS attack.