Payloads

Overview

Payloads are executables or scripts that can be delivered and executed through LimaCharlie's sensor.

Those payloads can be any executable or script natively understood by the endpoint. The main use case is to run something with specific functionality not available in the main LimaCharlie functionality. For example: custom executables provided by another vendor to cleanup a machine, forensic utilities or firmware-related utilities.

We encourage you to look at LimaCharlie native functionality first as it has several advantages:

• Usually has better performance.
• Data returned is always well structured JSON.
• Can be tasked automatically and Detection & Response Rules can be created from their data.
• Data returned is indexed and searchable.

It is possible to set the Payload's file extension on the endpoint by making the Payload name end with that extension. For example, naming a Payload extract_everything.bat, the Payload will be sent as a batch file (.bat) and executed as such. This is also true for PowerShell files (.ps1).

Lifecycle

Payloads are uploaded to the LimaCharlie platform and given a name. The task run can then be used with the --payload-name MY-PAYLOAD --arguments "-v EulaAccepted" can be used to run the payload with optional arguments.

The STDOUT and STDERR data will be returned in a related RECEIPT event, up to ~10 MB. If your payload generates more data, we recommend to pipe the data to a file on disk and use the log_get command to retrieve it.

The payload is retrieved by the sensor over HTTPS to the Ingestion API DNS endpoint. This DNS entry is available from the Sensor Download section of the web app if you need to allow it.

Upload / Download via REST

Creating and getting Payloads is done asynchronously. The relevant REST APIs will return specific signed URLs instead of the actual Payload. In the case of a retrieving an existing payload, simply doing an HTTP GET using the returned URL will download the payload content. When creating a Payload the returned URL should be used in an HTTP PUT using the URL like:

curl -X PUT "THE-SIGNED-URL-HERE" -H "Content-Type: application/octet-stream" --upload-file your-file.exe

Note that the signed URLs are only valid for a few minutes.

Permissions

Payloads are managed with two permissions:

• payload.ctrl allows you to create and delete payloads.
• payload.use allows you to run a given payload.