SIGNATURE_BASE_MAL_Chrysalis_Dllloader_Feb26

rule SIGNATURE_BASE_MAL_Chrysalis_Dllloader_Feb26 : FILE
{
	meta:
		description = "Detects DLL used to load Chrysalis backdoor, seen being used in the compromise of the infrastructure hosting Notepad++ by Chinese APT group Lotus Blossom"
		author = "X__Junior"
		id = "a2bf8cde-36a5-565d-9257-f1a4b2d67adc"
		date = "2026-02-02"
		modified = "2026-05-15"
		reference = "https://www.rapid7.com/blog/post/tr-chrysalis-backdoor-dive-into-lotus-blossoms-toolkit/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/lotusblossom_notepad_exploitation.yar#L1-L15"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "3bdc4c0637591533f1d4198a72a33426c01f69bd2e15ceee547866f65e26b7ad"
		logic_hash = "5e118287bd048788a746d412d00ddd2596224b30562d66c4441738fcc09cee87"
		score = 80
		quality = 85
		tags = "FILE"

	strings:
		$op1 = { 33 D2 8B C1 F7 F6 0F B6 C1 03 55 ?? 6B C0 ?? 32 02 88 04 0F 41 83 F9 ?? 72 }
		$op2 = { 0F B6 04 31 41 33 C2 69 D0 ?? ?? ?? ?? 3B CB 72 }

	condition:
		uint16( 0 ) == 0x5a4d and all of them
}