Prolock_Malware

YARA detection rule by Frank Boldewin (@r3c0nst)

Detects Prolock malware in encrypted and decrypted mode

rule Prolock_Malware {
	meta:
		description = "Detects Prolock malware in encrypted and decrypted mode"
		author = "Frank Boldewin (@r3c0nst)"
		reference = "https://raw.githubusercontent.com/fboldewin/YARA-rules/master/Prolock.Malware.yar"
		date = "2020-05-17"
		hash1 = "a6ded68af5a6e5cc8c1adee029347ec72da3b10a439d98f79f4b15801abd7af0"
		hash2 = "dfbd62a3d1b239601e17a5533e5cef53036647901f3fb72be76d92063e279178"
		
	strings:
		$DecryptionRoutine1 = {31 04 1A 81 3C 1A 90 90 90 90 74}
		$DecryptionRoutine2 = {83 C3 04 81 3C 1A C4 C4 C4 C4 74}
		$DecryptedString1 = "support981723721@protonmail.com" nocase ascii
		$DecryptedString2 = "Your files have been encrypted by ProLock Ransomware" nocase ascii
		$DecryptedString3 = "msaoyrayohnp32tcgwcanhjouetb5k54aekgnwg7dcvtgtecpumrxpqd.onion" nocase ascii
		$CryptoCode = {B8 63 51 E1 B7 31 D2 8D BE ?? ?? ?? ?? B9 63 51 E1 B7 81 C1 B9 79 37 9E}
		
	condition:
		((uint16(0) == 0x5A4D) or (uint16(0) == 0x4D42)) and filesize < 100KB and all of ($DecryptionRoutine*) or (1 of ($DecryptedString*) and $CryptoCode)
}

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

20457c60-3b7d-4900-a2ce-4154cc64d031

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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 ]]

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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 ]]

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