SEKOIA_Tinyfluff_Nodejs

rule SEKOIA_Tinyfluff_Nodejs : FILE
{
	meta:
		description = "Detect TinyFluff backdoor by OldGremlin"
		author = "Sekoia.io"
		id = "ca8cbd90-f275-4442-8354-b8b069e2efc3"
		date = "2022-04-20"
		modified = "2024-12-19"
		reference = "https://blog.group-ib.com/oldgremlin_comeback"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/tinyfluff_nodejs.yar#L1-L21"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		hash = "bd0a6a3628f268a37ac9d708d03f57feef5ed55e"
		hash = "bd0a6a3628f268a37ac9d708d03f57feef5ed55e"
		logic_hash = "7fa07b6ea32b914887bdcada0f9fda086bc29a44bfdf27e7433ef589192f4b82"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$s1 = "TinyFluff.pdb" fullword ascii
		$s2 = "node.exe" fullword wide

	condition:
		filesize < 500KB and uint16be( 0 ) == 0x4d5a and all of them
}