Windows: Deno writes files from remote HTTPS content into AppData

Alerts when Deno writes to user AppData while using remote HTTPS download-style paths.

FreeReviewedSigma · Low · v2

Product: windows
Category: file_event
Author: Josh Nickels, Michael Taggart (SigmaHQ), DRL 1.1
Published: 2025-05-22
Updated: 2026-07-31

ATT&CK techniques

Execution → C2

Recon
Resource Dev
Initial Access
Execution
- T1059.007JavaScript
- T1204User Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule matches Windows file events where the target path contains Deno-generated remote HTTPS directories and also includes a user AppData location (e.g., ':\Users\' and '\AppData\'). Attackers may abuse Deno to fetch content over HTTP(s) and place it into writable application data folders to stage execution artifacts. Telemetry relied on is Windows file event data, specifically the TargetFilename path reported by the endpoint.

Reporting behind it

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Windows: Deno writes files from remote HTTPS content into AppData

Pivot detection · T1105 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
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.

windows-deno-writing-files-to-appdata-from-remote-https-sources-6c0ce3b6

title: "Windows: Deno writes files from remote HTTPS content into AppData"
id: 7b502f3c-bf99-4c54-8a9a-a7f567497684
status: experimental
description: This rule matches Windows file events where the target path contains Deno-generated remote HTTPS directories and also includes a user AppData location (e.g., ':\Users\' and '\AppData\'). Attackers may abuse Deno to fetch content over HTTP(s) and place it into writable application data folders to stage execution artifacts. Telemetry relied on is Windows file event data, specifically the TargetFilename path reported by the endpoint.
references:
  - https://taggart-tech.com/evildeno/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_event/file_event_win_creation_deno.yml
author: Josh Nickels, Michael Taggart, Huntrule Team
date: 2025-05-22
tags:
  - attack.execution
  - attack.t1204
  - attack.t1059.007
  - attack.command-and-control
  - attack.t1105
logsource:
  category: file_event
  product: windows
detection:
  selection_path:
    TargetFilename|contains:
      - \deno\gen\
      - \deno\remote\https\
    TargetFilename|contains|all:
      - :\Users\
      - \AppData\
  condition: selection_path
falsepositives:
  - Legitimate usage of deno to request a file or bring a DLL to a host
level: low
license: DRL-1.1
related:
  - id: 6c0ce3b6-85e2-49d4-9c3f-6e008ce9796e
    type: derived

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