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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_JS_NPM_Supplychain_Attack_Sep25

Detects obfuscated JavaScript in NPM packages used in supply chain crypto stealer attacks in September 2025

MalwareSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth
Date
2025-09-09
Modified
2025-11-29
Score / Quality
85 / 85

What this rule detects

Detects obfuscated JavaScript in NPM packages used in supply chain crypto stealer attacks in September 2025

It defines 4 patterns (4 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-js-npm-supplychain-attack-sep25.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_JS_NPM_Supplychain_Attack_Sep25 : FILE
{
	meta:
		description = "Detects obfuscated JavaScript in NPM packages used in supply chain crypto stealer attacks in September 2025"
		author = "Florian Roth"
		id = "f083233e-348a-5b7d-a128-181c543a279c"
		date = "2025-09-09"
		modified = "2025-11-29"
		reference = "https://www.linkedin.com/feed/update/urn:li:activity:7370889385992437760/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/mal_npm_supply_chain_sep25.yar#L1-L21"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "16f6c756bc8ce5ef5d9aa1ded0f811ec0c9cee3d8f85cc151b8ca1df7b8a4337"
		logic_hash = "1b83d1bd79cdff02ed2fff7bf1feb57801ff9a933de1bd4f7ceecf738213ab4c"
		score = 85
		quality = 85
		tags = "FILE"

	strings:
		$x1 = "const _0x112fa8=_0x180f;(function(_0x13c8b9" ascii
		$fp1 = "<html"
		$fp2 = "<xml "
		$fp3 = "<?xml"

	condition:
		filesize < 200KB and 1 of ( $x* ) and not 1 of ( $fp* )
}

Strings (4 patterns)

IdentifierTypeValueModifiers
$x1text"const _0x112fa8=_0x180f;(function(_0x13c8b9"ascii
$fp1text"<html"
$fp2text"<xml "
$fp3text"<?xml"

Condition

filesize < 200KB and 1 of ( $x* ) and not 1 of ( $fp* )

In plain words (Heuristic)

  • The file must be smaller than 200KB (a cheap guard that skips large files).
  • At least 1 patterns in ( $x* ) must match.
  • At least 1 patterns in ( $fp* ) must match.

Test this rule in your browser

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Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

Open in editor

References

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

  • 16f6c756bc8ce5ef5d9aa1ded0f811ec0c9cee3d8f85cc151b8ca1df7b8a4337

Licence & attribution

Author: Florian Roth

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

Licence: Detection Rule License 1.1 (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: f083233e-348a-5b7d-a128-181c543a279c

Tags:FILE

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