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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_NK_MAL_M_Hunting_VEILEDSIGNAL_4

Detects VEILEDSIGNAL malware

APT / threat actorVeiledsignalSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Mandiant
Date
2023-04-20
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

Detects VEILEDSIGNAL malware

Associated malware family: Veiledsignal.

Targets: Windows PE.

It defines 6 patterns (4 text, 2 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
apt-nk-mal-m-hunting-veiledsignal-4.yarDetection Rule License 1.1
rule SIGNATURE_BASE_APT_NK_MAL_M_Hunting_VEILEDSIGNAL_4 : FILE
{
	meta:
		description = "Detects VEILEDSIGNAL malware"
		author = "Mandiant"
		id = "379e6471-3c4f-5c72-b8fd-17f481e89ac6"
		date = "2023-04-20"
		modified = "2023-12-05"
		reference = "https://www.mandiant.com/resources/blog/3cx-software-supply-chain-compromise"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_nk_tradingtech_apr23.yar#L98-L118"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "404b09def6054a281b41d309d809a428"
		hash = "c6441c961dcad0fe127514a918eaabd4"
		logic_hash = "2a875c39a43ff054ed5a6cf2fa1f17c2adc189452582763db8ceddfa652abfbf"
		score = 75
		quality = 85
		tags = "FILE"
		disclaimer = "This rule is meant for hunting and is not tested to run in a production environment"

	strings:
		$sb1 = { FF 15 FC 76 01 00 8B F0 85 C0 74 ?? 8D 50 01 [6-16] FF 15 [4] 48 8B D8 48 85 C0 74 ?? 89 ?? 24 28 44 8B CD 4C 8B C? 48 89 44 24 20 }
		$sb2 = { 33 D2 33 C9 FF 15 [4] 4C 8B CB 4C 89 74 24 28 4C 8D 05 [2] FF FF 44 89 74 24 20 33 D2 33 C9 FF 15 }
		$si1 = "CreateThread" fullword
		$si2 = "MultiByteToWideChar" fullword
		$si3 = "LocalAlloc" fullword
		$se1 = "DllGetClassObject" fullword

	condition:
		( uint16( 0 ) == 0x5A4D ) and ( uint32( uint32( 0x3C ) ) == 0x00004550 ) and ( uint16( uint32( 0x3C ) + 0x18 ) == 0x020B ) and all of them
}

Strings (6 patterns)

IdentifierTypeValueModifiers
$sb1hex{ FF 15 FC 76 01 00 8B F0 85 C0 74 ?? 8D 50 01 [6-16] FF 15 [4] 48 8B D8 48 85 C0 74 ?? 89 ?? 24 28 44 8B CD 4C 8B C? 48 89 44 24 20 }
$sb2hex{ 33 D2 33 C9 FF 15 [4] 4C 8B CB 4C 89 74 24 28 4C 8D 05 [2] FF FF 44 89 74 24 20 33 D2 33 C9 FF 15 }
$si1text"CreateThread"fullword
$si2text"MultiByteToWideChar"fullword
$si3text"LocalAlloc"fullword
$se1text"DllGetClassObject"fullword

Condition

( uint16( 0 ) == 0x5A4D ) and ( uint32( uint32( 0x3C ) ) == 0x00004550 ) and ( uint16( uint32( 0x3C ) + 0x18 ) == 0x020B ) and all of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in the rule must match.

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References

Sample hashes

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

  • 404b09def6054a281b41d309d809a428
  • c6441c961dcad0fe127514a918eaabd4

Licence & attribution

Author: Mandiant

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: 379e6471-3c4f-5c72-b8fd-17f481e89ac6

Metadata

disclaimerThis rule is meant for hunting and is not tested to run in a production environment

Tags:FILE

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