huntrule

Windows Browser Process Spawned with Inline URL Pointing to Suspicious File Extension

Flags Windows browser processes launched with an inline HTTP URL pointing to files with suspicious extensions.

FreeReviewedSigma · Medium · v2
Product
windows
Category
process_creation
Author
Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-01-11
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 creation where a common Windows browser executable is launched with a command-line argument containing an HTTP URL and ending in a potentially suspicious file extension (e.g., .exe, .dll, .ps1, .zip). Such behavior can be abused to coerce the browser into downloading arbitrary content or to reduce user visibility (for example, by using browser launch parameters). Telemetry relies on Windows process creation events including the initiating executable image path/name and the full command line arguments.

Reporting behind it

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Suspicious Certutil Download and Certificate Installation via Living-off-the-Land
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Suspicious Executable Download from Compromised CMS Client Scripts Path (via proxy)
Suspicious HijackLoader PNG Payload Retrieval via ClearFake
Malicious Download Piped to Shell via curl or wget (via process_creation)
Windows Browser Process Spawned with Inline URL Pointing to Suspicious File Extension
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.