Skip to content
yararules.org
Menu

YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_RANSOM_Darkbit_Feb23_2

Detects Go based DarkBit ransomware (garbled code; could trigger on other obfuscated samples, too)

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 Go based DarkBit ransomware (garbled code; could trigger on other obfuscated samples, too)

Associated malware family: Darkbit.

Targets: Windows PE.

It defines 6 patterns (4 text, 2 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-ransom-darkbit-feb23-2.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_RANSOM_Darkbit_Feb23_2 : FILE
{
	meta:
		description = "Detects Go based DarkBit ransomware (garbled code; could trigger on other obfuscated samples, too)"
		author = "Florian Roth"
		id = "f530815c-68e7-55f1-8e36-bc74a1059584"
		date = "2023-02-13"
		modified = "2023-12-05"
		reference = "https://www.hybrid-analysis.com/sample/9107be160f7b639d68fe3670de58ed254d81de6aec9a41ad58d91aa814a247ff?environmentId=160"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_ransom_darkbit_feb23.yar#L25-L45"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "9107be160f7b639d68fe3670de58ed254d81de6aec9a41ad58d91aa814a247ff"
		logic_hash = "577435536300902811612a3415e82420574c98345b91b21fb2bfd2bfde396bec"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$s1 = "runtime.initLongPathSupport" ascii fullword
		$s2 = "reflect." ascii
		$s3 = "    \"processes\": []," ascii fullword
		$s4 = "^!* %!(!" ascii fullword
		$op1 = { 4d 8b b6 00 00 00 00 48 8b 94 24 40 05 00 00 31 c0 87 82 30 03 00 00 b8 01 00 00 00 f0 0f c1 82 00 03 00 00 48 8b 44 24 48 48 8b 0d ba 1f 32 00 }
		$op2 = { 49 8d 49 01 0f 1f 00 48 39 d9 7c e2 b9 0b 00 00 00 49 89 d8 e9 28 fc ff ff e8 89 6c d7 ff }

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 20000KB and all of them
}

Strings (6 patterns)

IdentifierTypeValueModifiers
$s1text"runtime.initLongPathSupport"ascii fullword
$s2text"reflect."ascii
$s3text" \"processes\": [],"ascii fullword
$s4text"^!* %!(!"ascii fullword
$op1hex{ 4d 8b b6 00 00 00 00 48 8b 94 24 40 05 00 00 31 c0 87 82 30 03 00 00 b8 01 00 00 00 f0 0f c1 82 00 03 00 00 48 8b 44 24 48 48 8b 0d ba 1f 32 00 }
$op2hex{ 49 8d 49 01 0f 1f 00 48 39 d9 7c e2 b9 0b 00 00 00 49 89 d8 e9 28 fc ff ff e8 89 6c d7 ff }

Condition

uint16( 0 ) == 0x5a4d and filesize < 20000KB and all of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 20000KB (a cheap guard that skips large files).
  • All patterns in the rule must match.

Test this rule in your browser

Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.

Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

Open in editor

References

Sample hashes

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

  • 9107be160f7b639d68fe3670de58ed254d81de6aec9a41ad58d91aa814a247ff

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: f530815c-68e7-55f1-8e36-bc74a1059584

Tags:FILE

Related rules

More Darkbit rules