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TRELLIX_ARC_RANSOM_Darkside_DLL_May2021

Rule to detect Darkside Ransomware as a DLL

MalwareDarkSideTrellix Advanced Research CenterApache License 2.0Compiles with YARA-X
Author
TS @ McAfee ATR
Date
2021-05-14
Modified
2023-07-27
Score / Quality
75 / 70

What this rule detects

Rule to detect Darkside Ransomware as a DLL

Associated malware family: DarkSide.

It defines 8 patterns (3 text, 5 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

ransom-darkside-dll-may2021.yarApache License 2.0
rule TRELLIX_ARC_RANSOM_Darkside_DLL_May2021 : RANSOM FILE
{
	meta:
		description = "Rule to detect Darkside Ransomware as a DLL"
		author = "TS @ McAfee ATR"
		id = "e9d64637-dc8f-5650-81e1-34e27e6ee912"
		date = "2021-05-14"
		modified = "2023-07-27"
		reference = "https://github.com/advanced-threat-research/Yara-Rules/"
		source_url = "https://github.com/advanced-threat-research/Yara-Rules//blob/1919562a59f190bda60c982424f6a24c542ee3e0/ransomware/RANSOM_Darkside.yar#L26-L47"
		license_url = "https://github.com/advanced-threat-research/Yara-Rules//blob/1919562a59f190bda60c982424f6a24c542ee3e0/LICENSE"
		hash = "f587adbd83ff3f4d2985453cd45c7ab1"
		logic_hash = "39930b6f352642647ea6b80f941201b93d6a9defd42cb75f9e4f7239ff17a4ec"
		score = 75
		quality = 70
		tags = "RANSOM, FILE"
		rule_type = "Public"
		rule_version = "v1"
		malware_type = "Ransom"

	strings:
		$s1 = "encryptor2.dll" wide ascii
		$s2 = "DisableThreadLibraryCalls" wide ascii
		$s3 = "KERNEL32.dll" wide ascii
		$pattern1 = {D24DC8855EDD487B3CD2D545F11031E1FA85C2F2440712445F67D105B326533A77BA75B3383A98CE97EAA2B95798DCFA6B75B5573662F9ED5DC9B7D2E582FD94104E210F3EA62A1826B26B952FFBD5A70A97E6EC3D14794577A2980A0ED1EE02CA291623DD3721A7E68223EDA56F9E1325FE36E191D5C41F7227D55EDC3D5B9359C819}
		$pattern2 = {87FC982E066F585B73D417C0D5F75B86B9F9F8286B4CC42BB2053912D595A68C07C0EDD0159AC785880C5483E246D3501F6523D05078B9B7510711423948D4CB367C83C0833BD04AD6DC655E1BEEA38770470BB48B6EBA70944E952526E4D87A03BAA485D7B4DA1318A00EF07FA76C0D}
		$pattern3 = {1B6F099F1C3C62BBF5543FA03B919C7BF5E477D256CE79D98C55ACE8D69CDC9373B2F0A2B51414776D5226B74BF9A7CB935C9DD04BCFC19FC81418F7A39244A730697E1BC05418BF41DE50E4C8609533591CE80617D476E686B36CF2AE914CB3AFD720A33C0D5DE438F1CD0B}
		$pattern4 = {5060E373F1D3B3BB8D15C851BBFC73F60390681C488F7C0B80FC2EDBC1ED88CEA82014B9223A70EA0BB7DD0D2560A29D39381FEE7B73AE22683AE05C369918F8C5772678A9F29CEF65854238D1C2B762CC12706637154F57A9}
		$pattern5 = {EE452560DBD5A4F46FB562C9C707C8D014BB8F1C18E4467E249F5AC69A87954F5B69650B7A759CE2DD075E99CBCBA37A9C5A0650EDF06285F8F990AF6B94FBA08E3C0B2EBDE3C155ECDB06C30F95D76695}

	condition:
		filesize >= 45KB and filesize <= 70KB and all of ( $s* ) and 4 of ( $pattern* )
}

Strings (8 patterns)

IdentifierTypeValueModifiers
$s1text"encryptor2.dll"wide ascii
$s2text"DisableThreadLibraryCalls"wide ascii
$s3text"KERNEL32.dll"wide ascii
$pattern1hex{D24DC8855EDD487B3CD2D545F11031E1FA85C2F2440712445F67D105B326533A77BA75B3383A98CE97EAA2B95798DCFA6B75B5573662F9ED5DC9B7D2E582FD94104E210F3EA62A1826B26B952FFBD5A …
$pattern2hex{87FC982E066F585B73D417C0D5F75B86B9F9F8286B4CC42BB2053912D595A68C07C0EDD0159AC785880C5483E246D3501F6523D05078B9B7510711423948D4CB367C83C0833BD04AD6DC655E1BEEA38 …
$pattern3hex{1B6F099F1C3C62BBF5543FA03B919C7BF5E477D256CE79D98C55ACE8D69CDC9373B2F0A2B51414776D5226B74BF9A7CB935C9DD04BCFC19FC81418F7A39244A730697E1BC05418BF41DE50E4C860953 …
$pattern4hex{5060E373F1D3B3BB8D15C851BBFC73F60390681C488F7C0B80FC2EDBC1ED88CEA82014B9223A70EA0BB7DD0D2560A29D39381FEE7B73AE22683AE05C369918F8C5772678A9F29CEF65854238D1C2B76 …
$pattern5hex{EE452560DBD5A4F46FB562C9C707C8D014BB8F1C18E4467E249F5AC69A87954F5B69650B7A759CE2DD075E99CBCBA37A9C5A0650EDF06285F8F990AF6B94FBA08E3C0B2EBDE3C155ECDB06C30F95D76 …

Condition

filesize >= 45KB and filesize <= 70KB and all of ( $s* ) and 4 of ( $pattern* )

In plain words (Heuristic)

  • The file must be smaller than 70KB (a cheap guard that skips large files).
  • The file must be larger than 45KB.
  • All patterns in ( $s* ) must match.
  • At least 4 patterns in ( $pattern* ) must match.

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References

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

  • f587adbd83ff3f4d2985453cd45c7ab1

Licence & attribution

Author: TS @ McAfee ATR

Source repository: Trellix Advanced Research Center @ 1919562a59

Licence: Apache License 2.0 (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: e9d64637-dc8f-5650-81e1-34e27e6ee912

Metadata

rule_typePublic
rule_versionv1
malware_typeRansom

Tags:RANSOMFILE

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