Name:Windows Curl Upload to Remote Destination id:42f8f1a2-4228-11ec-aade-acde48001122 version:18 date:None author:Michael Haag, Splunk status:production type:TTP Description:The following analytic detects the use of Windows Curl.exe to upload a file to a remote destination.
It identifies command-line arguments such as `-T`, `--upload-file`, `-d`, `--data`, and `-F` in process execution logs.
This activity is significant because adversaries may use Curl to exfiltrate data or upload malicious payloads. If confirmed malicious, this could lead to data breaches or further compromise of the system.
Analysts should review parallel processes and network logs to determine if the upload was successful and isolate the endpoint if necessary. Data_source:
-Sysmon EventID 1
-Windows Event Log Security 4688
-CrowdStrike ProcessRollup2
-Cisco Network Visibility Module Flow Data
search:| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime
from datamodel=Endpoint.Processes where
( Processes.process_name=curl.exe OR Processes.original_file_name=Curl.exe ) Processes.process IN ( "*-T *", "*--upload-file *", "*-d *", "*--data *", "*-F *" )
how_to_implement:The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process. known_false_positives:False positives may be limited to source control applications and may be required to be filtered out. References: -https://everything.curl.dev/usingcurl/uploads -https://techcommunity.microsoft.com/t5/containers/tar-and-curl-come-to-windows/ba-p/382409 -https://twitter.com/d1r4c/status/1279042657508081664?s=20 drilldown_searches: name:'View the detection results for - "$user$" and "$dest$"' search:'%original_detection_search% | search user = "$user$" dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$user$" and "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'7d' latest_offset:'0' analytic_story:['Cisco Network Visibility Module Analytics', 'Compromised Windows Host', 'Ingress Tool Transfer', 'Microsoft WSUS CVE-2025-59287', 'NPM Supply Chain Compromise', 'PromptLock', 'Axios Supply Chain Post Compromise']
