huntrule

Windows curl.exe Suspicious Download to Local File Paths

Flags curl.exe executions on Windows that appear to download to local files in suspicious directories with risky file extensions.

FreeReviewedSigma · High · v2
Product
windows
Category
process_creation
Author
Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2020-07-03
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

C2

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule flags process starts of curl.exe on Windows where the command line suggests the download output is written to common user or system locations such as AppData, Temp, Public, Desktop, PerfLogs, ProgramData, or Windows Temp. It also matches curl command lines that end with file extensions commonly used for downloaded content (e.g., .txt, .vbs, .vbe, images, and temporary script/file formats). Attackers commonly use curl to retrieve remote content and stage it locally, so correlating process creation telemetry with suspicious output paths and extensions helps identify likely download-and-stage activity.

Reporting behind it

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Windows curl.exe Suspicious Download to Local File Paths
Pivot detection · T1105 · 9 related

Changelog

v2
  1. v2
    Candidate ingested via manual entry.2026-07-31
  2. v1
    No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.