Suspicious Curl File Upload - Linux (via process_creation)

title: Suspicious Curl File Upload - Linux (via process_creation)
id: 9368907b-9804-5bdf-9589-2e7de47dc5e7
status: stable
description: This rule detects an anomalous curl process start the adds a file to a web request
references:
    - https://attack.mitre.org/techniques/T1105/
    - https://attack.mitre.org/techniques/T1567/
    - https://twitter.com/d1r4c/status/1279042657508081664
    - https://medium.com/@petehouston/upload-files-with-curl-93064dcccc76
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1105/T1105.md#atomic-test-19---curl-upload-file
    - https://curl.se/docs/manpage.html
    - https://www.trendmicro.com/en_us/research/22/i/how-malicious-actors-abuse-native-linux-tools-in-their-attacks.html
author: Huntrule Team
date: 2026-04-29
tags:
    - attack.exfiltration
    - attack.command-and-control
    - attack.t1567
    - attack.t1105
logsource:
    category: process_creation
    product: linux
detection:
    selection_img:
        Image|endswith: '/curl'
    selection_cli:
        - CommandLine|contains:
              - ' --form'
              - ' --upload-file '
              - ' --data '
              - ' --data-'
        - CommandLine|re: '\s-[FTd]\s'
    filter_optional_localhost:
        CommandLine|contains:
            - '://localhost'
            - '://127.0.0.1'
    condition: all of selection_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: medium