YARA · SEKOIA.IO Community

SEKOIA_Apt_Kimsuky_Vbs_Powershell_Downloader

Detects VBS/Powershell Downloader used by Kimsuky

APT / threat actorKimsukySEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X

Author: Sekoia.io
Date: 2022-08-30
Modified: 2024-12-19
Score / Quality: 75 / 80

What this rule detects

Detects VBS/Powershell Downloader used by Kimsuky

Associated malware family: Kimsuky.

It defines 3 patterns (3 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-kimsuky-vbs-powershell-downloader.yarDetection Rule License 1.1

rule SEKOIA_Apt_Kimsuky_Vbs_Powershell_Downloader : FILE
{
	meta:
		description = "Detects VBS/Powershell Downloader used by Kimsuky"
		author = "Sekoia.io"
		id = "4c9af11f-802b-4ffe-9783-90fc2ee53809"
		date = "2022-08-30"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_kimsuky_vbs_powershell_downloader.yar#L1-L18"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "dc24ca206a3122b34be978287f907b12c809f76058fe9355bbd00b3159b0a4d4"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$ = "& WScript.ScriptFullName &" ascii fullword
		$ = "/c schtasks /create /sc minute /mo 5 /tn"
		$ = "pOwErsHeLl -ep bypass -encodedCommand"

	condition:
		filesize < 200KB and 2 of them
}

Strings (3 patterns)

Identifier	Type	Value	Modifiers
$	text	"& WScript.ScriptFullName &"	ascii fullword
$	text	"/c schtasks /create /sc minute /mo 5 /tn"
$	text	"pOwErsHeLl -ep bypass -encodedCommand"

Condition

filesize < 200KB and 2 of them

In plain words (Heuristic)

The file must be smaller than 200KB (a cheap guard that skips large files).
At least 2 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/SEKOIA-IO/Community

Licence & attribution

Author: Sekoia.io

Source repository: SEKOIA.IO Community @ a438a5901a

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: 4c9af11f-802b-4ffe-9783-90fc2ee53809

Metadata

version	1.0
classification	TLP:CLEAR

Tags:FILE

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