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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_NK_MAL_M_Hunting_VEILEDSIGNAL_2

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 (5 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
apt-nk-mal-m-hunting-veiledsignal-2.yarDetection Rule License 1.1
rule SIGNATURE_BASE_APT_NK_MAL_M_Hunting_VEILEDSIGNAL_2 : FILE
{
	meta:
		description = "Detects VEILEDSIGNAL malware"
		author = "Mandiant"
		id = "1b96c2f0-1c57-593e-9630-a72d43eb857e"
		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#L57-L76"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "404b09def6054a281b41d309d809a428"
		logic_hash = "62f74faa8f136f4dc63a4b703cffcb97b438cc4f180d5d127d1fc4b86d3cd1d1"
		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 = { C1 E0 05 4D 8? [2] 33 D0 45 69 C0 7D 50 BF 12 8B C2 41 FF C2 C1 E8 07 33 D0 8B C2 C1 E0 16 41 81 C0 87 D6 12 00 }
		$si1 = "CryptBinaryToStringA" fullword
		$si2 = "BCryptGenerateSymmetricKey" fullword
		$si3 = "CreateThread" fullword
		$ss1 = "ChainingModeGCM" wide
		$ss2 = "__tutma" 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{ C1 E0 05 4D 8? [2] 33 D0 45 69 C0 7D 50 BF 12 8B C2 41 FF C2 C1 E8 07 33 D0 8B C2 C1 E0 16 41 81 C0 87 D6 12 00 }
$si1text"CryptBinaryToStringA"fullword
$si2text"BCryptGenerateSymmetricKey"fullword
$si3text"CreateThread"fullword
$ss1text"ChainingModeGCM"wide
$ss2text"__tutma"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

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: 1b96c2f0-1c57-593e-9630-a72d43eb857e

Metadata

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

Tags:FILE

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