CVE-2020-5289
Read permissions not enforced for client provided filter expressions in Elide.
Description
### Impact It is possible for an adversary to "guess and check" the value of a model field they do not have access to assuming they can read at least one other field in the model. The adversary can construct filter expressions for an inaccessible field to filter a collection. The presence or absence of models in the returned collection can be used to reconstruct the value of the inaccessible field. For example, a User model has two fields: _name_ and _role_. The adversary has read permissions to see the _name_ field of the User collection but not the _role_. By constructing a filter like the one below, the adversary can determine which users have admin role by presence or absence in the returned collection: `filter=role=="Admin"` ### Patches Resolved in Elide 4.5.14 and greater. ### Workarounds The adversary can only access the fields if a model includes fields with different read permission levels (some less secure and some more secure). Model security can be adjusted by restricting read permissions on existing models. ### References Fixed in https://github.com/yahoo/elide/pull/1236 ### For more information If you have any questions or comments about this advisory: * Open an issue in [elide](https://github.com/yahoo/elide) * Contact us at [spectrum](https://spectrum.chat/elide?tab=posts)
How to fix CVE-2020-5289
To remediate CVE-2020-5289, upgrade the affected package to a fixed version below.
- —upgrade to 4.5.14 or later
Is CVE-2020-5289 being exploited?
Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 4.5.14