YARA · ESET malware-ioc

ESET_Apt_Windows_Invisimole_CPL_Loader

CPL loader

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

Author: ESET Research
Date: 2021-05-17
Score / Quality: 75 / 80

What this rule detects

CPL loader

Associated malware family: Invisimole.

Targets: Windows PE.

It defines 7 patterns (7 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-windows-invisimole-cpl-loader.yarBSD 2-Clause License

rule ESET_Apt_Windows_Invisimole_CPL_Loader : FILE
{
	meta:
		description = "CPL loader"
		author = "ESET Research"
		id = "feff8627-6085-5835-ac1b-d4522245f7db"
		date = "2021-05-17"
		modified = "2021-05-17"
		reference = "https://github.com/eset/malware-ioc/"
		source_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/invisimole/invisimole.yar#L97-L118"
		license_url = "https://github.com/eset/malware-ioc/blob/17baf44964a77368e9149f4f593eb098beddf1c5/LICENSE"
		logic_hash = "cd5c19e14faa7fd3758b30193ccf2bed3692ad29d8216466523ca25d2abcfe88"
		score = 75
		quality = 80
		tags = "FILE"
		license = "BSD 2-Clause"
		version = "1"

	strings:
		$s1 = "WScr%steObject(\"WScr%s.Run(\"::{20d04fe0-3a%s30309d}\\\\::{21EC%sDD-08002B3030%s\", 0);"
		$s2 = "\\Control.js" wide
		$s3 = "\\Control Panel.lnk" wide
		$s4 = "FPC 3.0.4 [2019/04/13] for x86_64 - Win64"
		$s5 = "FPC 3.0.4 [2019/04/13] for i386 - Win32"
		$s6 = "imageapplet.dat" wide
		$s7 = "wkssvmtx"

	condition:
		uint16( 0 ) == 0x5A4D and ( 3 of them )
}

Strings (7 patterns)

Identifier	Type	Value	Modifiers
$s1	text	"WScr%steObject(\"WScr%s.Run(\"::{20d04fe0-3a%s30309d}\\\\::{21EC%sDD-08002B3030%s\", 0);"
$s2	text	"\\Control.js"	wide
$s3	text	"\\Control Panel.lnk"	wide
$s4	text	"FPC 3.0.4 [2019/04/13] for x86_64 - Win64"
$s5	text	"FPC 3.0.4 [2019/04/13] for i386 - Win32"
$s6	text	"imageapplet.dat"	wide
$s7	text	"wkssvmtx"

Condition

uint16( 0 ) == 0x5A4D and ( 3 of them )

In plain words (Heuristic)

The file must start with “MZ” — a Windows executable (PE).
At least 3 patterns in the rule must match.

Test this rule in your browser

Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.

Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

Open in editor

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: feff8627-6085-5835-ac1b-d4522245f7db

Metadata

version	1

Tags:FILE

ESET_Apt_Windows_Invisimole
APT / threat actorESET malware-ioc· ESET Research· 2021-05-17
ESET_Apt_Windows_Invisimole_DNS_Downloader
APT / threat actorESET malware-ioc· ESET Research· 2021-05-17
ESET_Apt_Windows_Invisimole_Logs
APT / threat actorESET malware-ioc· ESET Research· 2021-05-17
ESET_Apt_Windows_Invisimole_SFX_Dropper
APT / threat actorESET malware-ioc· ESET Research· 2021-05-17
ESET_Apt_Windows_Invisimole_RC2CL_Backdoor
APT / threat actorESET malware-ioc· ESET Research· 2021-05-17
ESET_Apt_Windows_Invisimole_Wrapper_DLL
APT / threat actorESET malware-ioc· ESET Research· 2021-05-17
ESET_Apt_Windows_Invisimole_C2
APT / threat actorESET malware-ioc· ESET Research· 2021-05-17
ESET_Invisimole_Blob_PRIVATE
MalwareESET malware-ioc· ESET Research· 2021-05-17

More Invisimole rules