Detection rules › Sigma
Curl File Upload To File Sharing Websites
Detects usage of curl to upload files to known file sharing domains, which may indicate data exfiltration.
Known false positives
- Legitimate file uploads to these services by administrators or developers
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Exfiltration |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 1: Process creation |
Rule body
title: Curl File Upload To File Sharing Websites
id: e328cc73-f92a-42fb-b3fa-7c2cffda981a
related:
- id: 00bca14a-df4e-4649-9054-3f2aa676bc04
type: derived
- id: 7d1aaf3d-4304-425c-b7c3-162055e0b3ab
type: similar
status: experimental
description: Detects usage of curl to upload files to known file sharing domains, which may indicate data exfiltration.
author: Swachchhanda Shrawan Poudel (Nextron Systems)
references:
- https://unit42.paloaltonetworks.com/advanced-backdoor-squidoor/
date: 2026-03-29
tags:
- attack.exfiltration
- attack.t1567.002
logsource:
category: process_creation
product: windows
detection:
selection_img:
- Image|endswith: '\curl.exe'
- OriginalFileName: 'curl.exe'
selection_cli_domain:
CommandLine|contains:
- '0x0.st'
- 'bashupload.com'
- 'chunk.io'
- 'file.io'
- 'filebin.net'
- 'pastebin'
- 'send.firefox.com'
- 'temp.sh'
- 'transfer.sh'
- 'ufile.io'
- 'uploadfiles.io'
- 'wetransfer.com'
- 'x0.at'
selection_cli_flags:
- CommandLine|contains:
- ' --form'
- ' --upload-file'
- ' --data'
- ' -X POST'
- ' --request POST '
- CommandLine|re:
- '\s-[FTd]\s' # We use regex to ensure a case sensitive argument detection
- '\s-sT\s'
condition: all of selection_*
falsepositives:
- Legitimate file uploads to these services by administrators or developers
level: high
Stages and Predicates
Stage 0: condition
all of selection_*Stage 1: selection_img
selection_img:
- Image|endswith: '\curl.exe'
- OriginalFileName: 'curl.exe'
Stage 2: selection_cli_domain
selection_cli_domain:
CommandLine|contains:
- '0x0.st'
- 'bashupload.com'
- 'chunk.io'
- 'file.io'
- 'filebin.net'
- 'pastebin'
- 'send.firefox.com'
- 'temp.sh'
- 'transfer.sh'
- 'ufile.io'
- 'uploadfiles.io'
- 'wetransfer.com'
- 'x0.at'
Stage 3: selection_cli_flags
selection_cli_flags:
- CommandLine|contains:
- ' --form'
- ' --upload-file'
- ' --data'
- ' -X POST'
- ' --request POST '
- CommandLine|re:
- '\s-[FTd]\s'
- '\s-sT\s'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
CommandLine | match |
| field:"CommandLine" kind:match |
CommandLine | regex_match |
| field:"CommandLine" kind:regex_match |
Image | ends_with |
| field:"Image" kind:ends_with value:"\curl.exe" |
OriginalFileName | eq |
| field:"OriginalFileName" kind:eq value:"curl.exe" |