> For the complete documentation index, see [llms.txt](https://cortex-docs.paloaltonetworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cortex-docs.paloaltonetworks.com/cortex-xsiam/detect-investigate-and-respond-to-threats/investigation-and-response/research-a-known-threat.md).

# Research a known threat

This topic describes the steps you can take to investigate a lead. A lead can be:

* An issue from a non-Palo Alto Networks system with information relevant to endpoints or firewalls.
* Users or hosts that have been reported as acting abnormally.
* Information from online articles or other external threat intelligence that provides well-defined characteristics of the threat.

To research a known threat

1. Use threat intelligence to build a Cortex Query Language (XQL) query using the Query Builder.

   For example, if external threat intelligence indicates a confirmed threat involving specific files or behaviors, search for those characteristics.
2. Review and refine the query results by using filters and running follow-up queries to find the information you are looking for.
3. Select an event of interest, and open the **Causality view**.

   Review the chain of execution and data, navigate through the processes on the tree, and analyze the information.
4. Open the **Timeline** to view the sequence of events over time. If deemed malicious, take action using one or more of the response actions.
5. Inspect the information again, and identify any characteristics you can use to create a BIOC or correlation rule.

   If you can create a BIOC or correlation rule, test and tune it as needed. For more information, see [Create a correlation rule](/cortex-xsiam/detect-investigate-and-respond-to-threats/threat-management/detection-rules/what-are-detection-rules/whats-a-correlation-rule/create-a-correlation-rule.md) and [Create a BIOC rule](/cortex-xsiam/detect-investigate-and-respond-to-threats/threat-management/detection-rules/what-are-detection-rules/whats-a-bioc/create-a-bioc-rule.md).


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://cortex-docs.paloaltonetworks.com/cortex-xsiam/detect-investigate-and-respond-to-threats/investigation-and-response/research-a-known-threat.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.