YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_MAL_VEILEDSIGNAL_Backdoor_Apr23_3

Detects malicious VEILEDSIGNAL backdoor

APT / threat actorVeiledsignalSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X

Author: X__Junior
Date: 2023-04-29
Modified: 2023-12-05
Score / Quality: 80 / 85

What this rule detects

Detects malicious VEILEDSIGNAL backdoor

Associated malware family: Veiledsignal.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-mal-veiledsignal-backdoor-apr23-3.yarDetection Rule License 1.1

rule SIGNATURE_BASE_APT_MAL_VEILEDSIGNAL_Backdoor_Apr23_3
{
	meta:
		description = "Detects malicious VEILEDSIGNAL backdoor"
		author = "X__Junior"
		id = "6b6f984e-242a-5b84-baa9-6311992cde9b"
		date = "2023-04-29"
		modified = "2023-12-05"
		reference = "https://symantec-enterprise-blogs.security.com/blogs/threat-intelligence/xtrader-3cx-supply-chain"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/gen_mal_3cx_compromise_mar23.yar#L394-L410"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "595392959b609caf088d027a23443cf2fefd043607ccdec3de19ad3bb43a74b1"
		logic_hash = "58f860926db4a7dfefbd39ee35efaa0081b7e31a361efce02f5144266ab652a6"
		score = 80
		quality = 85
		tags = ""

	strings:
		$op1 = { 4C 8B CB 4C 89 74 24 ?? 4C 8D 05 ?? ?? ?? ?? 44 89 74 24 ?? 33 D2 33 C9 FF 15}
		$op2 = { 89 7? 24 ?? 44 8B CD 4C 8B C? 48 89 44 24 ?? 33 D2 33 C9 FF 15}
		$op3 = { 8B 54 24 ?? 4C 8D 4C 24 ?? 45 8D 46 ?? 44 89 74 24 ?? 48 8B CB FF 15}
		$op4 = { 48 8D 44 24 ?? 45 33 C9 41 B8 01 00 00 40 48 89 44 24 ?? 41 8B D5 48 8B CF FF 15}

	condition:
		all of them
}

Strings (4 patterns)

Identifier	Type	Value
$op1	hex	{ 4C 8B CB 4C 89 74 24 ?? 4C 8D 05 ?? ?? ?? ?? 44 89 74 24 ?? 33 D2 33 C9 FF 15}
$op2	hex	{ 89 7? 24 ?? 44 8B CD 4C 8B C? 48 89 44 24 ?? 33 D2 33 C9 FF 15}
$op3	hex	{ 8B 54 24 ?? 4C 8D 4C 24 ?? 45 8D 46 ?? 44 89 74 24 ?? 48 8B CB FF 15}
$op4	hex	{ 48 8D 44 24 ?? 45 33 C9 41 B8 01 00 00 40 48 89 44 24 ?? 41 8B D5 48 8B CF FF 15}

Condition

all of them

In plain words (Heuristic)

All patterns in the rule must match.

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References

https://symantec-enterprise-blogs.security.com/blogs/threat-intelligence/xtrader-3cx-supply-chain

Sample hashes

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

595392959b609caf088d027a23443cf2fefd043607ccdec3de19ad3bb43a74b1

Licence & attribution

Author: X__Junior

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: 6b6f984e-242a-5b84-baa9-6311992cde9b

SIGNATURE_BASE_APT_MAL_VEILEDSIGNAL_Backdoor_Apr23
APT / threat actorSignature Base (Florian Roth / Nextron)· X__Junior· 2023-04-20
SIGNATURE_BASE_APT_MAL_VEILEDSIGNAL_Backdoor_Apr23_2
APT / threat actorSignature Base (Florian Roth / Nextron)· X__Junior· 2023-04-29
SIGNATURE_BASE_APT_MAL_VEILEDSIGNAL_Backdoor_Apr23_4
APT / threat actorSignature Base (Florian Roth / Nextron)· X__Junior· 2023-04-29
SIGNATURE_BASE_SUSP_APT_MAL_VEILEDSIGNAL_Backdoor_Apr23
Suspicious / huntingSignature Base (Florian Roth / Nextron)· X__Junior· 2023-04-20
SIGNATURE_BASE_APT_NK_MAL_M_Hunting_VEILEDSIGNAL_1
APT / threat actorSignature Base (Florian Roth / Nextron)· Mandiant· 2023-04-20
SIGNATURE_BASE_APT_NK_MAL_M_Hunting_VEILEDSIGNAL_2
APT / threat actorSignature Base (Florian Roth / Nextron)· Mandiant· 2023-04-20
SIGNATURE_BASE_APT_NK_MAL_M_Hunting_VEILEDSIGNAL_3
APT / threat actorSignature Base (Florian Roth / Nextron)· Mandiant· 2023-04-20
SIGNATURE_BASE_APT_NK_MAL_M_Hunting_VEILEDSIGNAL_4
APT / threat actorSignature Base (Florian Roth / Nextron)· Mandiant· 2023-04-20

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