SEKOIA_Ursnif

rule SEKOIA_Ursnif : FILE
{
	meta:
		description = "Ursnif Payload"
		author = "Sekoia.io"
		id = "ac392af3-c344-453c-9427-5bb46223e01c"
		date = "2024-12-19"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/ursnif.yar#L1-L23"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "fd3c3be5ede0a980b44560cfb9b8c4c1ee322091fa86bc9143f30dc900053c2b"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$crypto64_1 = {41 8B 02 ?? C1 [0-1] 41 33 C3 45 8B 1A 41 33 C0 D3 C8 41 89 02 49 83 C2 04 83 C2 FF 75 D?}
		$crypto64_2 = {44 01 44 24 10 FF C1 41 8B C0 D1 64 24 10 33 C3 41 8B D8 FF 4C 24 10 41 33 C3 01 44 24 10 D3 C8 01 44 24 10 41 89 02 49 83 C2 04 83 C2 FF 75 C3}
		$crypto64_3 = {33 C6 ?? C7 [0-1] 49 83 C2 04 33 C3 8B F1 8B CF D3 C8 89 02 48 83 C2 04 41 83 C3 FF 75 ?? 45 85 C9 75 ?? 41 83 E0 03}
		$crypto64_4 = {41 8B 02 41 8B CB 41 83 F3 01 33 C3 41 8B 1A C1 E1 03 41 33 C0 D3 C8 41 89 02 49 83 C2 04 83 C2 FF 75 C6}
		$decrypt_config64 = {44 8B D9 33 C0 45 33 C9 44 33 1D ?? ?? ?? 00 ?? ?? D2 ?? ?? D2 74 ?? 4C 8D 42 10 45 3B 0A 73 2? 45 39 58 F8 75 1C 41 F6 40 FC 01 74 12}
		$crypto32_1 = {01 45 FC D1 65 FC FF 4D FC 33 C1 33 45 0C 01 45 FC 43 8A CB D3 C8 8B CE 01 45 FC 89 02 83 C2 04 FF 4D 08 75 CD}
		$crypto32_2 = {33 C1 33 44 24 10 43 8A CB D3 C8 8B CE 89 02 83 C2 04 FF 4C 24 0C 75 D9}
		$decrypt_config32 = {8B ?? 08 5? 33 F? 3B [1-2] 74 14 A1 0? ?? ?? ?? 35 ?? ?? ?? ?? 50 8B D? E8 ?? D? 00 00 EB 02 33 C0 ?B ?? ?? ?? ?? ?? ?? ?? 74 14 8D 4D ?? ?? ?? 50 FF D? 85 C0 74 08}

	condition:
		true and uint16( 0 ) == 0x5A4D and ( ( $decrypt_config64 and any of ( $crypto64* ) ) or ( $decrypt_config32 and any of ( $crypto32* ) ) )
}