Cortex 2: a Sneak Peek

Unless you’ve been living in a cave with no Internet connection during the last year or so, you certainly know a thing or two about Cortex, TheHive’s perfect sidekick, which allows you to analyze observables, at scale, using its 30+ analyzers.

As of this writing, the latest version of Cortex is 1.1.4. Cortex can be queried using its Web UI for quick assessment of an observable. But the true power of Cortex is unleashed when the engine is queried through its REST API, either from TheHive (which can leverage multiple Cortex instances), from alternative SIRPs (Security Incident Response Platforms), Threat Intelligence Platforms and programs thanks to Cortex4py. Indeed, when Cortex is called through the API, it can analyze large sets of observables. Each analysis generates a job. Jobs are queued on first-created, first-executed basis.

However, Cortex 1 has three limitations:

  1. It does not support authentication. If you install it and don’t shield it from abuse (using a firewall for example), anyone can submit analysis jobs and consume your query quotas for subscription-based, commercial services, for example. Non-CSIRT/CERT/SOC personnel or threat actors can also view all the jobs you’ve executed (what observables you have analyzed, using which analyzers and what the associated results were).
  2. It does not support rate-limiting. All it takes to ruin your quotas is an unexperienced analyst who’d create a case in TheHive from a MISP event containing thousands of attributes, select them all from the newly created case, and run them through various Cortex analyzers.
  3. It has no persistence. If you restart the Cortex service or the host it runs on, all your analysis results will disappear. Please note that if you query Cortex from TheHive, the latter will keep a copy of all the reports generated by the analyzers.

Moreover, analyzer configuration is not as easy as we’d like it to be. Enters Cortex 2.

Authentication, Organizations, Configuration and Rate Limiting

Cortex 2, due for release in February 2018, almost a year after the release of the first version, will support all the authentication methods TheHive supports: LDAP, Active Directory, local accounts, API keys and/or SSO using X.509 certificates (an experimental feature as of this writing).

Once created, users will be associated to an organization. Each organization has its own configuration: which analyzers are enabled, associated API keys and/or authentication credentials for services (VirusTotal, PassiveTotal, MISP, …) and a query quota.

For example, if you have an overall quota on VT for 10,000 queries/month, you can limit the number of queries to 5000 for org A, 3000 for org B and leave 2000 for other uses. Rate limits can be configured per month or per day.

Screen Shot 2017-12-15 at 17.16.06
Cortex 2 — Architecture

More on Organizations

Organizations will be ideal for multi-tenant Cortex instances deployed, for a example, by the central CSIRT of a large company. They can then create orgs for their regional SOCs. Commercial teams such as MSSPs will also be able to use a single instance to serve all their customers.

Graphical Interface Enhancements

Administrators will not have to edit /etc/cortex/application.conf by hand to enable and configure analyzers per org. They will be able to do so from the Web UI. The Web UI will also allow them to manage users, orgs and authentication tokens when applicable.

Report Persistence and Freshness

Cortex 2 will use ES 5 for storage, like TheHive. That way, you will no longer lose your existing jobs when you reboot the Cortex host or restart the service. You will also be able to query historical results to monitor changes and so on. We will also add an optional parameter to make Cortex 2 to serve the latest report generated by an analyzer if it is called again, on the same observable in the last X seconds or minutes. That way, we’ll avoid running the same queries again and again for the same observable and thus consuming quotas and CPU and storage resources.

Pricing

Cortex 2 is a significant development over Cortex 1 … but it’ll still cost you nothing as it will remain free and open source. We could feel you itching when you started reading this paragraph. Chill out! But if you are willing to support the project, you can donate to Creative Source, the non-profit organization we have created to sustain TheHive, Cortex and Hippocampe in the long run. Interested? Contact us at support@thehive-project.org then.