Sigma rule: Suspicious Curl.EXE Download

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-c4590034fba1, updated 2023-02-21T00:00:00.000Z.

Rule

Title: Suspicious Curl.EXE Download
Status: test
Level: high
Author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
Date: 2020-07-03
Modified: 2023-02-21
File: rules/windows/process_creation/proc_creation_win_curl_susp_download.yml
Commit: ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects a suspicious curl process start on Windows and outputs the requested document to a local file

Log source

product: windows
category: process_creation

Detection

selection_curl:
    - Image|endswith: '\curl.exe'
    - Product: 'The curl executable'
selection_susp_locations:
    CommandLine|contains:
        - '%AppData%'
        - '%Public%'
        - '%Temp%'
        - '%tmp%'
        - '\AppData\'
        - '\Desktop\'
        - '\Temp\'
        - '\Users\Public\'
        - 'C:\PerfLogs\'
        - 'C:\ProgramData\'
        - 'C:\Windows\Temp\'
selection_susp_extensions:
    CommandLine|endswith:
        - '.dll'
        - '.gif'
        - '.jpeg'
        - '.jpg'
        - '.png'
        - '.temp'
        - '.tmp'
        - '.txt'
        - '.vbe'
        - '.vbs'
filter_optional_git_windows:
    # Example FP
    #   CommandLine: "C:\Program Files\Git\mingw64\bin\curl.exe" --silent --show-error --output C:/Users/test/AppData/Local/Temp/gfw-httpget-jVOEoxbS.txt --write-out %{http_code} https://gitforwindows.org/latest-tag.txt
    ParentImage: 'C:\Program Files\Git\usr\bin\sh.exe'
    Image: 'C:\Program Files\Git\mingw64\bin\curl.exe'
    CommandLine|contains|all:
        - '--silent --show-error --output '
        - 'gfw-httpget-'
        - 'AppData'
condition: selection_curl and 1 of selection_susp_* and not 1 of filter_optional_*

False positives (as the rule lists them)

Unknown

MITRE ATT&CK ids this rule names

T1105

Related rules

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_curl_susp_download.yml

Sources and licences

SigmaHQ
"Suspicious Curl.EXE Download" by Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_curl_susp_download.yml.
Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License
Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Suspicious Curl.EXE Download",
entity page, dataset version ref-c4590034fba1, updated 2023-02-21T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/e218595b-bbe7-4ee5-8a96-f32a24ad3468 (accessed 2026-11-03).
Underlying source: SigmaHQ rule e218595b-bbe7-4ee5-8a96-f32a24ad3468, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.