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DITEKSHEN_MALWARE_Win_Nworm

Detects NWorm/N-W0rm payload

MalwareNwormditekSHen detectionBSD 2-Clause LicenseCompiles with YARA-X
Author
ditekSHen
Date
2020-11-06
Modified
2024-11-01
Score / Quality
75 / 75

What this rule detects

Detects NWorm/N-W0rm payload

Associated malware family: Nworm.

Targets: Windows PE.

It defines 12 patterns (12 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

malware-win-nworm.yarBSD 2-Clause License
rule DITEKSHEN_MALWARE_Win_Nworm : FILE
{
	meta:
		description = "Detects NWorm/N-W0rm payload"
		author = "ditekSHen"
		id = "06546ccf-8914-5b1c-942f-99664b9ecf44"
		date = "2020-11-06"
		modified = "2024-11-01"
		reference = "https://github.com/ditekshen/detection"
		source_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/yara/malware.yar#L3423-L3443"
		license_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/LICENSE.txt"
		logic_hash = "a1397a057422be260b5bdf1eb58571e95c259c132cc2518b39e1524a0eda9c66"
		score = 75
		quality = 75
		tags = "FILE"
		clamav_sig = "MALWARE.Win.Trojan.NWorm"

	strings:
		$id1 = "N-W0rm" ascii
		$id2 = "N_W0rm" ascii
		$x1 = "pongPing" fullword wide
		$x2 = "|NW|" fullword wide
		$s1 = "runFile" fullword wide
		$s2 = "runUrl" fullword wide
		$s3 = "killer" fullword wide
		$s4 = "powershell" fullword wide
		$s5 = "wscript.exe" fullword wide
		$s6 = "ExecutionPolicy Bypass -WindowStyle Hidden -NoExit -File \"" fullword wide
		$s7 = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36" fullword wide
		$s8 = "Start-Sleep -Seconds 1.5; Remove-Item -Path '" fullword wide

	condition:
		uint16( 0 ) == 0x5a4d and ( ( 1 of ( $id* ) and ( 1 of ( $x* ) or 3 of ( $s* ) ) ) or ( all of ( $x* ) and 2 of ( $s* ) ) or 7 of ( $s* ) or 10 of them )
}

Strings (12 patterns)

IdentifierTypeValueModifiers
$id1text"N-W0rm"ascii
$id2text"N_W0rm"ascii
$x1text"pongPing"fullword wide
$x2text"|NW|"fullword wide
$s1text"runFile"fullword wide
$s2text"runUrl"fullword wide
$s3text"killer"fullword wide
$s4text"powershell"fullword wide
$s5text"wscript.exe"fullword wide
$s6text"ExecutionPolicy Bypass -WindowStyle Hidden -NoExit -File \""fullword wide
$s7text"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36"fullword wide
$s8text"Start-Sleep -Seconds 1.5; Remove-Item -Path '"fullword wide

Condition

uint16( 0 ) == 0x5a4d and ( ( 1 of ( $id* ) and ( 1 of ( $x* ) or 3 of ( $s* ) ) ) or ( all of ( $x* ) and 2 of ( $s* ) ) or 7 of ( $s* ) or 10 of them )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in ( $x* ) must match.
  • At least 1 patterns in ( $id* ) must match.
  • At least 1 patterns in ( $x* ) must match.
  • At least 3 patterns in ( $s* ) must match.
  • At least 2 patterns in ( $s* ) must match.
  • At least 7 patterns in ( $s* ) must match.
  • At least 10 patterns in the rule must match.

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References

Licence & attribution

Author: ditekSHen

Source repository: ditekSHen detection @ e76c93dcde

Licence: BSD 2-Clause License (repository licence)

Copyright notice: Copyright 2021 by ditekSHen (https://github.com/ditekshen/detection).

Original rule

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

Rule id: 06546ccf-8914-5b1c-942f-99664b9ecf44

Metadata

clamav_sigMALWARE.Win.Trojan.NWorm

Tags:FILE