DITEKSHEN_MALWARE_Win_Epsilon

rule DITEKSHEN_MALWARE_Win_Epsilon : FILE
{
	meta:
		description = "Detects Epsilon ransomware"
		author = "ditekSHen"
		id = "c5561a0d-85ac-5137-a97e-310aa03eb787"
		date = "2020-11-06"
		modified = "2024-11-01"
		reference = "https://github.com/ditekshen/detection"
		source_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/yara/malware.yar#L4137-L4169"
		license_url = "https://github.com/ditekshen/detection/blob/e76c93dcdedff04076380ffc60ea54e45b313635/LICENSE.txt"
		logic_hash = "cc4481ddb6f5fd52a0bc901dde4c34ccf79024cd68605245df0dcbea22d0adee"
		score = 75
		quality = 75
		tags = "FILE"

	strings:
		$s1 = ".Speak \"" wide
		$s2 = "chkUpdateRegistry" fullword wide
		$s3 = "/C choice /C Y /N /D Y /T 1 & Del \"" fullword wide
		$s4 = "CreateObject(\"sapi.spvoice\")" fullword wide
		$s5 = "READ_ME.hta" wide
		$s6 = "WScript.Sleep(" wide
		$s7 = "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run" fullword wide
		$s8 = "<div class='bold'>Files are encrypted* but not deleted.</div>" ascii
		$e1 = { 72 00 75 00 6e 00 64 00 6c 00 6c 00 2e 00 65 00
                78 00 65 00 00 09 2e 00 74 00 78 00 74 00 00 09
                2e 00 64 00 6f 00 63 00 00 0b 2e 00 64 00 6f 00
                63 00 78 00 00 09 2e 00 78 00 6c 00 73 00 00 0d
                2e 00 69 00 6e 00 64 00 65 00 78 00 00 09 2e 00
                70 00 64 00 66 00 00 09 2e 00 7a 00 69 00 70 00
                00 09 2e 00 72 00 61 00 72 00 00 09 2e 00 63 00
                73 00 73 00 00 09 2e 00 6c 00 6e 00 6b 00 00 0b
                2e 00 78 00 6c 00 73 00 78 00 00 09 2e 00 70 00
                70 00 74 00 00 0b 2e 00 70 00 70 00 74 00 78 00
                00 09 2e 00 6f 00 64 00 }
		$e2 = { 68 00 74 00 6d 00 00 07 2e 00 6d 00 6c 00 00 07
                43 00 3a 00 5c 00 00 07 44 00 3a 00 5c 00 00 07
                45 00 3a 00 5c 00 00 07 46 00 3a 00 5c 00 00 07
                47 00 3a 00 5c 00 00 07 5a 00 3a 00 5c 00 00 07
                41 00 3a 00 5c 00 00 0f 63 00 6d 00 64 00 2e 00
                65 00 78 00 65 }

	condition:
		uint16( 0 ) == 0x5a4d and ( 6 of ( $s* ) or ( all of ( $e* ) and 4 of ( $s* ) ) )
}