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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_Cobaltstrike_Resources_Beacon_Dll_V3_8_1

Cobalt Strike's resources/beacon.dll Versions 3.8

Hack toolCobalt StrikeSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
gssincla@google.com
Date
2022-11-18
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

Cobalt Strike's resources/beacon.dll Versions 3.8

Associated malware family: Cobalt Strike.

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

Summary generated from the rule's metadata and condition.

Rule source

cobaltstrike-resources-beacon-dll-v3-8-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_Cobaltstrike_Resources_Beacon_Dll_V3_8_1
{
	meta:
		description = "Cobalt Strike's resources/beacon.dll Versions 3.8"
		author = "gssincla@google.com"
		id = "6c65cbf8-2c60-5315-b3b2-48dfcee75733"
		date = "2022-11-18"
		modified = "2023-12-05"
		reference = "https://cloud.google.com/blog/products/identity-security/making-cobalt-strike-harder-for-threat-actors-to-abuse"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/gen_gcti_cobaltstrike.yar#L1020-L1061"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "67b6557f614af118a4c409c992c0d9a0cc800025f77861ecf1f3bbc7c293d603"
		logic_hash = "cde078a6ae7d0d835900e85498cf5ae20663ba8d5d3f912810e157261561e16a"
		score = 75
		quality = 85
		tags = ""

	strings:
		$version_sig = { 48 57 8B F9 83 F8 4B 0F 87 5D 03 00 00 FF 24 }
		$decoder = { 80 B0 [4] ?? 40 3D 00 10 00 00 7C F1 }
		$xmrig_srcpath = "C:/Users/SKOL-NOTE/Desktop/Loader/script.go"
		$c2_1 = "ns7.softline.top" xor
		$c2_2 = "ns8.softline.top" xor
		$c2_3 = "ns9.softline.top" xor

	condition:
		$version_sig and $decoder and ( 2 of ( $c2_* ) or $xmrig_srcpath )
}

Strings (6 patterns)

IdentifierTypeValueModifiers
$version_sighex{ 48 57 8B F9 83 F8 4B 0F 87 5D 03 00 00 FF 24 }
$decoderhex{ 80 B0 [4] ?? 40 3D 00 10 00 00 7C F1 }
$xmrig_srcpathtext"C:/Users/SKOL-NOTE/Desktop/Loader/script.go"
$c2_1text"ns7.softline.top"xor
$c2_2text"ns8.softline.top"xor
$c2_3text"ns9.softline.top"xor

Condition

$version_sig and $decoder and ( 2 of ( $c2_* ) or $xmrig_srcpath )

In plain words (Heuristic)

  • At least 2 patterns in ( $c2_* ) must match.
  • Pattern $version_sig must be present.
  • Pattern $decoder must be present.
  • Pattern $xmrig_srcpath must be present.

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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).

  • 67b6557f614af118a4c409c992c0d9a0cc800025f77861ecf1f3bbc7c293d603

Licence & attribution

Author: gssincla@google.com

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: 6c65cbf8-2c60-5315-b3b2-48dfcee75733

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