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GCTI_Cobaltstrike_Resources_Beacon_Dll_V3_5_Hf1_And_3_5_1

Cobalt Strike's resources/beacon.dll Versions 3.5-hf1 and 3.5.1 (3.5.x)

Hack toolCobalt StrikeGoogle Cloud Threat Intelligence (GCTI)Apache License 2.0Compiles with YARA-X
Author
gssincla@google.com
Date
2022-11-18
Modified
2023-12-04
Score / Quality
75 / 85

What this rule detects

Cobalt Strike's resources/beacon.dll Versions 3.5-hf1 and 3.5.1 (3.5.x)

Associated malware family: Cobalt Strike.

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

Summary generated from the rule's metadata and condition.

Rule source

cobaltstrike-resources-beacon-dll-v3-5-hf1-and-3-5-1.yarApache License 2.0
rule GCTI_Cobaltstrike_Resources_Beacon_Dll_V3_5_Hf1_And_3_5_1
{
	meta:
		description = "Cobalt Strike's resources/beacon.dll Versions 3.5-hf1 and 3.5.1 (3.5.x)"
		author = "gssincla@google.com"
		id = "1532596e-be0e-58c2-8d3b-5120c793d677"
		date = "2022-11-18"
		modified = "2023-12-04"
		reference = "https://cloud.google.com/blog/products/identity-security/making-cobalt-strike-harder-for-threat-actors-to-abuse"
		source_url = "https://github.com/chronicle/GCTI/blob/1c5fd42b1895098527fde00c2d9757edf6b303bb/YARA/CobaltStrike/CobaltStrike__Resources_Beacon_Dll_All_Versions_MemEnabled.yara#L594-L625"
		license_url = "https://github.com/chronicle/GCTI/blob/1c5fd42b1895098527fde00c2d9757edf6b303bb/LICENSE"
		hash = "c78e70cd74f4acda7d1d0bd85854ccacec79983565425e98c16a9871f1950525"
		logic_hash = "c2e975678815638803b04261d46bca216bc0b2f894a1f72fd0d5b949493401d1"
		score = 75
		quality = 85
		tags = ""

	strings:
		$version_sig = { 48 57 8B F1 83 F8 43 0F 87 07 03 00 00 FF 24 }
		$decoder = { 80 B0 [4] ?? 40 3D 00 10 00 00 7C F1 }

	condition:
		all of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$version_sighex{ 48 57 8B F1 83 F8 43 0F 87 07 03 00 00 FF 24 }
$decoderhex{ 80 B0 [4] ?? 40 3D 00 10 00 00 7C F1 }

Condition

all of them

In plain words (Heuristic)

  • All patterns in the rule 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).

  • c78e70cd74f4acda7d1d0bd85854ccacec79983565425e98c16a9871f1950525

Licence & attribution

Author: gssincla@google.com

Source repository: Google Cloud Threat Intelligence (GCTI) @ 1c5fd42b18

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: 1532596e-be0e-58c2-8d3b-5120c793d677

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