SUSP_JS_NPM_SetupScript_Nov25

YARA detection rule by Marius Benthin · NOASSERTION

Detects suspicious JavaScript which exits silently and checks operating system

rule SUSP_JS_NPM_SetupScript_Nov25 {
   meta:
      description = "Detects suspicious JavaScript which exits silently and checks operating system"
      author = "Marius Benthin"
      date = "2025-11-24"
      modified = "2025-12-15"
      reference = "https://www.aikido.dev/blog/shai-hulud-strikes-again-hitting-zapier-ensdomains"
      hash = "a3894003ad1d293ba96d77881ccd2071446dc3f65f434669b49b3da92421901a"
      score = 70
      id = "2d102efd-681a-5af1-b4fe-3489e5e7f8f2"
   strings:
      $sa1 = "require('child_process')"
      $sa2 = "process.platform ==="

      $sb1 = "().catch((e"
      $sb2 = "process.exit(0)"
   condition:
      filesize < 100KB
      and all of ($sa*)
      and $sb1 in (filesize - 50..filesize)
      and $sb2 in (filesize - 30..filesize)
}

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

f7577c5a-ca7d-4a12-af4b-9479d9fd7aab

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

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