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Identity assurance
When users access online services, they want to be confident that nobody else can log in pretending to be them, access their sensitive personal data or use their identity to make fraudulent claims. They want to be confident that their data and services are secure and their privacy is protected. Institutions and Service Providers that offer online services also need to verify a users user's identity to make sure only the right users are accessing the right information. These are distinct That is why identity assurance is needed.
How identity assurance works
SURFconext Strong Authentication is designed to establish that a user is who he says he is, and that the authentication token he wishes to use for future strong authentication is indeed in possession of the user. It is the role of the institution (Identity Providers) to make sure the registration is valid and genuine.
One of the benefits of SURFconext Strong Authentication is that most users will be able to complete the registration process online. After completion of the registration process the user has to visit a Service Desk or IT Helpdesk once to have its token activated.
In general there are three types of authentication factors:
- Something the user knows (password or PIN)
- Something the user has (mobile phone or token)
- Something the user is (fingerprint or other bio-metric data)
Strong authentication refers to the use of more than one of these factors. Generally this results in a higher level of assurance (LoA) about the user.
| Level of assurance | Authentication Assurance | Identity assurance | Characteristics |
|---|---|---|---|
| LoA 1 | Username/password | No extra validation of the user's identity | For access to basic resources with little or no risk |
| LoA 1.5 | Username/password + second factor | No extra validation of the user's identity | Protects the user and resources from compromised passwords |
| LoA 2 | Username/password + tiqr, SMS or AzureMFA | The identity of the user is validated | For high level of confidence in the asserted identity. Often used for access to high risk resources |
| LoA 3 | Username/password + YubiKey or FIDO2 | The identity of the user is validated | Same as LoA2, but with more secure authentication methods. |
A service or institution needs to choose which level of assurance is appropriate for protection. There are several ways a LoA can be requested for a specific service or part of a service.
Second Factor Only (SFO) authentication
With Second Factor Only (SFO) Authentication "Level" is used to indicate the authentication strength: LoA does not apply. There are three levels:
- Level 1.5: any SURFsecureID second factor, no extra validation of the user's identity
- Level 2: SMS, Tiqr or Azure MFA authentication AND the identity of the user is validated
- Level 3: YubiKey or FIDO2 token authentication AND the identity of the user is validated
Assurance level explained
There are several international standards for identity assurance, like NIST (US), eIDAS (Europe, previously STORK) and ISO29115. SURFsecureID is based on ISO29115. The four levels of identity assurance commonly used are:
| LoA 1 | Little or no confidence in the asserted identity |
| LoA 2 | Some confidence in the asserted identity |
| LoA 3 | High confidence in the asserted identity |
| LoA 4 | Very high confidence in the asserted identity |
The different specifications elaborate on the meaning of these labels by specifying requirements for:
- registration
- authentication token management
- online authentication
The resulting assurance level depends on the combination of these aspects. The aspect with the lowest score determines the overall assurance level (a chain is only as strong as its weakest link).
Once the identity provider has verified the user's identity, the registered token of the user will be activated. The user can then use his token as a secure secure means of signing in.
Level of assurance requirements: risk based
Not all services need to know who their users are. For most services it is sufficient to know a user belongs to a certain institution, or
Other services will need to be more confident that the user is indeed who he says he is; for example, if a user will be able to see privacy sensitive information, or can edit data like grades in student information systems or financial system
The required level of assurance can be estimated on:
- the importance of the data and
- the potential damages if these data were to be obtained or modified by unauthorized users
These risks must be assessed Each service will need to assess risks to be able to decide what the level of assurance is needed . SURF has published guidelines on how to make such a risk assessment. These guidelines are published herefor your service (see also SURFnet guidelines).
Level of assurance vs robustness of infrastructure
The LoAs described by NIST and STORK primarily focus on the robustness of the authentication. The robustness of the technical infrastructure is mostly beyond their scope.
It is assumed that proper measures are in place taken to prevent potential authentication protocol threats such as eavesdropping, man-in-the-middle, replaying, and hijacking. Attacks are not limited to the authentication protocol itself. Other attacks include the use of malicious code to compromise authentication tokens, insider threats to compromise authentication tokens, social engineering to get a subscriber to reveal his password to the attacker, “shoulder-surfing”, fooling claimants into using an insecure protocol, when they think that they are using a secure protocol, or intentionally denying ever having registerd registered by subscribers who deliberately compromise their tokens.
Other types of threats are (SAML) assertion related such as modification, disclosure, repudiation, reuse , or redirect. Countermeasures should be in place taken to prevent these attacks as well. It goes too far to describe for each LoA the amount and strength of the required countermeasures. Most of these countermeasures are addressed in the information security policy of the stakeholders. NIST 800-63-1 also gives some guidelines. The most important ones are the use of digital signatures to sign assertions with and the use of SSL/TLS to secure the communication channel.
Both control measures are required to fulfil fulfill the requirements for LoA2 and LoA3 and are already in place in SURFconext Strong Authentication. NIST SP 800-63-1 recommends the CSP (i.e. SURFconext Strong Authentication) for LoA2 to “employ appropriately tailored security controls from the low baseline of security controls defined in [NIST SP 800-53 ] and to ensure that the minimum assurance requirements associated with the low baseline are satisfied”. For LoA3 security controls from the moderate baseline of security controls are required.SURFsecureID.
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Please note that SURFconext Strong Authentication solely SURFsecureID solely focuses on authentication LoA. No LoA is assigned to the individual attributes of the user's identity.
Several attributes provided by the IdP
...
(e.g. first and last name
...
, e-mail address) will be validated during registration and identification. In theory a LoA could be assigned to these attributes
...
, which in attribute-based access control scenario’s
...
could
...
make authorization more reliable. There are
...
however
...
some arguments against doing this:
- Mixing attributes with different LoA’s is complex
...
- There is no suitable way to express differing LoA’s for attributes in SAML assertions
...
- The registration process will
...
- be more complex
...
Because of these arguments SURFsecureID solely focuses on authentication LoA.