Ransom_Win32_Chaicha

YARA detection rule by roadwy

Ransom:Win32/Chaicha,SIGNATURE_TYPE_PEHSTR_EXT,0a 00 0a 00 0a 00 00

rule Ransom_Win32_Chaicha{
	meta:
		description = "Ransom:Win32/Chaicha,SIGNATURE_TYPE_PEHSTR_EXT,0a 00 0a 00 0a 00 00 "
		
	strings :
		$a_01_0 = {59 6f 75 72 20 66 69 6c 65 73 2c 20 70 68 6f 74 6f 73 2c 20 64 6f 63 75 6d 65 6e 74 73 2c 20 64 61 74 61 62 61 73 65 73 20 61 6e 64 20 6f 74 68 65 72 20 69 6d 70 6f 72 74 61 6e 74 20 66 69 6c 65 73 20 61 72 65 20 65 6e 63 72 79 70 74 65 64 20 61 6e 64 20 68 61 76 65 20 74 68 65 20 65 78 74 65 6e 73 69 6f 6e 3a 20 2e 53 41 56 45 66 69 6c 65 73 } 		$a_01_1 = {41 6c 6c 20 79 6f 75 72 20 66 69 6c 65 73 2c 20 64 6f 63 75 6d 65 6e 74 73 2c 20 70 68 6f 74 6f 73 2c 20 64 61 74 61 62 61 73 65 73 20 61 6e 64 20 6f 74 68 65 72 20 69 6d 70 6f 72 74 61 6e 74 20 66 69 6c 65 73 20 61 72 65 20 65 6e 63 72 79 70 74 65 64 20 61 6e 64 20 68 61 76 65 20 74 68 65 20 65 78 74 65 6e 73 69 6f 6e 3a 20 2e 57 48 59 } 		$a_01_2 = {21 21 21 53 41 56 45 5f 46 49 4c 45 53 5f 49 4e 46 4f 21 21 21 2e 74 78 74 } 		$a_01_3 = {21 21 21 57 48 59 5f 5f 4d 59 5f 5f 46 49 4c 45 53 5f 5f 4e 4f 54 5f 5f 4f 50 45 4e 21 21 21 2e 74 78 74 } 		$a_01_4 = {42 4d 2d 32 63 58 6f 6e 7a 6a 39 6f 76 6e 35 71 64 58 32 4d 72 77 4d 4b 34 6a 33 71 43 71 75 58 42 4b 6f 34 68 40 62 69 74 6d 65 73 73 61 67 65 2e 63 68 } 		$a_01_5 = {42 4d 2d 32 63 55 6d 31 48 47 35 4e 46 66 39 66 59 4d 68 50 7a 4c 68 6a 6f 42 64 58 71 64 65 32 36 69 42 6d 32 40 62 69 74 6d 65 73 73 61 67 65 2e 63 68 } 		$a_01_6 = {41 66 74 65 72 20 70 75 72 63 68 61 73 65 20 79 6f 75 20 77 69 6c 6c 20 73 74 61 72 74 20 64 65 63 72 79 70 74 20 73 6f 66 74 77 61 72 65 } 		$a_01_7 = {4f 6e 6c 79 20 77 65 20 63 61 6e 20 67 69 76 65 20 79 6f 75 20 74 68 69 73 20 6b 65 79 20 61 6e 64 20 6f 6e 6c 79 20 77 65 20 63 61 6e 20 72 65 63 6f 76 65 72 20 79 6f 75 72 20 66 69 6c 65 73 2e } 		$a_01_8 = {79 6f 75 20 63 61 6e 20 73 65 6e 64 20 75 73 20 61 20 31 2d 33 20 61 6e 79 20 6e 6f 74 20 76 65 72 79 20 62 69 67 20 65 6e 63 72 79 70 74 65 64 20 66 69 6c 65 73 20 61 6e 64 20 77 65 20 77 69 6c 6c 20 73 65 6e 64 20 79 6f 75 20 62 61 63 6b 20 69 74 20 69 6e 20 61 20 6f 72 69 67 69 6e 61 6c 20 66 6f 72 6d 20 46 52 45 45 2e } 		$a_03_9 = {50 72 69 63 65 20 66 6f 72 20 64 65 63 72 79 70 74 69 6f 6e 20 24 ?? 30 30 2e } 	condition:
		((#a_01_0  & 1)*4+(#a_01_1  & 1)*4+(#a_01_2  & 1)*4+(#a_01_3  & 1)*4+(#a_01_4  & 1)*4+(#a_01_5  & 1)*4+(#a_01_6  & 1)*1+(#a_01_7  & 1)*1+(#a_01_8  & 1)*1+(#a_03_9  & 1)*1) >=10
 
}

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

8adbc30d-c94e-4f10-9a24-a79a5a4ef01f

Propose edits, view related rules, and engage with the community through comments.

Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

Community Discussion