YARA · ESET malware-ioc

ESET_Apt_Windows_TA410_Flowcloud_Dll_Hijacking_Strings

Matches filenames inside TA410 FlowCloud malicious DLL.

APT / threat actorESET malware-iocBSD 2-Clause LicenseCompiles with YARA-X

Author: ESET Research
Date: 2021-10-12
Modified: 2022-04-27
Score / Quality: 75 / 80

What this rule detects

Matches filenames inside TA410 FlowCloud malicious DLL.

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-windows-ta410-flowcloud-dll-hijacking-strings.yarBSD 2-Clause License

rule ESET_Apt_Windows_TA410_Flowcloud_Dll_Hijacking_Strings : FILE
{
	meta:
		description = "Matches filenames inside TA410 FlowCloud malicious DLL."
		author = "ESET Research"
		id = "6636d4d0-0a7f-5971-a7f4-58803042d874"
		date = "2021-10-12"
		modified = "2022-04-27"
		reference = "https://github.com/eset/malware-ioc/"
		source_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/ta410/ta410.yar#L498-L517"
		license_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/LICENSE"
		logic_hash = "e8082d4216364a12ba395f772b5caed94b3068d26a2b3a97ef711d61a82f65b3"
		score = 75
		quality = 80
		tags = "FILE"
		license = "BSD 2-Clause"
		version = "1"

	strings:
		$dat1 = "emedres.dat" wide
		$dat2 = "vviewres.dat" wide
		$dat3 = "setlangloc.dat" wide
		$dll1 = "emedres.dll" wide
		$dll2 = "vviewres.dll" wide
		$dll3 = "setlangloc.dll" wide

	condition:
		uint16( 0 ) == 0x5a4d and ( all of ( $dat* ) or all of ( $dll* ) )
}

Strings (6 patterns)

Identifier	Type	Value	Modifiers
$dat1	text	"emedres.dat"	wide
$dat2	text	"vviewres.dat"	wide
$dat3	text	"setlangloc.dat"	wide
$dll1	text	"emedres.dll"	wide
$dll2	text	"vviewres.dll"	wide
$dll3	text	"setlangloc.dll"	wide

Condition

uint16( 0 ) == 0x5a4d and ( all of ( $dat* ) or all of ( $dll* ) )

In plain words (Heuristic)

The file must start with “MZ” — a Windows executable (PE).
All patterns in ( $dat* ) must match.
All patterns in ( $dll* ) must match.

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References

https://github.com/eset/malware-ioc/

Licence & attribution

Author: ESET Research

Source repository: ESET malware-ioc @ 17baf44964

Licence: BSD 2-Clause License (stated in the rule's own meta)

“BSD 2-Clause”

Original rule

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

Rule id: 6636d4d0-0a7f-5971-a7f4-58803042d874

Metadata

version	1

Tags:FILE

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