Detection: Windows Curl Upload to Remote Destination
Description
The following analytic identifies the use of Windows Curl.exe uploading a file to a remote destination.
-T or --upload-file is used when a file is to be uploaded to a remotge destination.
-d or --data POST is the HTTP method that was invented to send data to a receiving web application, and it is, for example, how most common HTML forms on the web work.
HTTP multipart formposts are done with -F, but this appears to not be compatible with the Windows version of Curl. Will update if identified adversary tradecraft.
Adversaries may use one of the three methods based on the remote destination and what they are attempting to upload (zip vs txt). During triage, review parallel processes for further behavior. In addition, identify if the upload was successful in network logs. If a file was uploaded, isolate the endpoint and review.
Annotations
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Implementation
To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint_Processess datamodel.
Known False Positives
False positives may be limited to source control applications and may be required to be filtered out.
Associated Analytic Story
Risk Based Analytics (RBA)
| Risk Message | Risk Score | Impact | Confidence |
|---|---|---|---|
| An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest_device_id$ by user $dest_user_id$ uploading a file to a remote destination. | 80 | 80 | 100 |
References
Version: 4