MISP contains an improper input validation vulnerability in the decaying model import functionality. The import endpoint was intended to create a new decaying model belonging exclusively to the importing users organisation, with the default flag forced to off.
However, the application stripped only the top-level id and uuid fields and pinned org_id and default on the outer array before saving the data flat. A user with decaying-model permissions could supply a nested model key carrying its own primary key, organisation identifier, and default flag, which bypassed those guards during the save operation.
Impact:
A user with perm_decaying could overwrite an existing decaying model belonging to another organisation in place, altering its name, formula, parameters, or ownership.
A user could create or modify a model flagged as the organisation default, affecting scoring behaviour for other users.
A user could reassign a models organisation to an arbitrary value.
Preconditions:
Authenticated user with decaying-model permission (perm_decaying).
Network access to the MISP instance.
Affected: <2.5.48.
Weakness
The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.
Potential Mitigations
- Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
- Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page.
- One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
Related Attack Patterns
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- https://cwe.mitre.org/data/definitions/127.html
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- https://cwe.mitre.org/data/definitions/45.html
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- https://cwe.mitre.org/data/definitions/60.html
- https://cwe.mitre.org/data/definitions/647.html
- https://cwe.mitre.org/data/definitions/668.html
- https://cwe.mitre.org/data/definitions/76.html
- https://cwe.mitre.org/data/definitions/77.html
- https://cwe.mitre.org/data/definitions/87.html