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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_RANSOM_Darkbit_Feb23_1

Detects indicators found in DarkBit ransomware

MalwareDarkbitSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth
Date
2023-02-13
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

Detects indicators found in DarkBit ransomware

Associated malware family: Darkbit.

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-ransom-darkbit-feb23-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_RANSOM_Darkbit_Feb23_1 : FILE
{
	meta:
		description = "Detects indicators found in DarkBit ransomware"
		author = "Florian Roth"
		id = "d209a0c2-f649-5fb1-9ecd-f1c35caa796f"
		date = "2023-02-13"
		modified = "2023-12-05"
		reference = "https://twitter.com/idonaor1/status/1624703255770005506?s=12&t=mxHaauzwR6YOj5Px8cIeIw"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_ransom_darkbit_feb23.yar#L2-L23"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "ba1baea7cb7362160c4b00b0355000a789b238c1ec82b840479c04028e6ca3ab"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$s1 = ".onion" ascii
		$s2 = "GetMOTWHostUrl"
		$x1 = "hus31m7c7ad.onion"
		$x2 = "iw6v2p3cruy"
		$xn1 = "You will receive decrypting key after the payment."

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 10MB and ( 1 of ( $x* ) or 2 of them ) or 4 of them or ( filesize < 10MB and $xn1 )
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$s1text".onion"ascii
$s2text"GetMOTWHostUrl"
$x1text"hus31m7c7ad.onion"
$x2text"iw6v2p3cruy"
$xn1text"You will receive decrypting key after the payment."

Condition

uint16( 0 ) == 0x5a4d and filesize < 10MB and ( 1 of ( $x* ) or 2 of them ) or 4 of them or ( filesize < 10MB and $xn1 )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 10MB (a cheap guard that skips large files).
  • At least 1 patterns in ( $x* ) must match.
  • At least 2 patterns in the rule must match.
  • At least 4 patterns in the rule must match.
  • Pattern $xn1 must be present.

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References

Licence & attribution

Author: Florian Roth

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

Licence: Detection Rule License 1.1 (repository licence)

Original rule

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

Rule id: d209a0c2-f649-5fb1-9ecd-f1c35caa796f

Tags:FILE

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