SEKOIA_Apt_Gamaredon_Gamaredon_Lnk_Usb_Spreader_Encoded

rule SEKOIA_Apt_Gamaredon_Gamaredon_Lnk_Usb_Spreader_Encoded : FILE
{
	meta:
		description = "Detects encoded version of Gamaredon LNK USB Spreader"
		author = "Sekoia.io"
		id = "e42bb654-d1aa-4219-b3da-dd4053d59a83"
		date = "2023-06-19"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/apt_gamaredon_gamaredon_lnk_usb_spreader_encoded.yar#L1-L19"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		hash = "28358a4a6acdcdfc6d41ea642220ef98c63b9c3ef2268449bb02d2e2e71e7c01"
		logic_hash = "81ab55330b3003cb698ade7e14eaea5fb03e5d2d3dd310b7db682aeef9b51f6e"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$s1 = "[System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String(" ascii
		$s2 = " 1000000){" base64
		$s3 = "+\"\\$" base64
		$s4 = ",3\";" base64

	condition:
		$s1 at 0 and 3 of them and filesize < 4000
}