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GCTI_Cobaltstrike_Sleeve_Beacon_X64_V4_1_And_V_4_2

Cobalt Strike's sleeve/beacon.x64.dll Versions 4.1 and 4.2

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 sleeve/beacon.x64.dll Versions 4.1 and 4.2

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-sleeve-beacon-x64-v4-1-and-v-4-2.yarApache License 2.0
rule GCTI_Cobaltstrike_Sleeve_Beacon_X64_V4_1_And_V_4_2
{
	meta:
		description = "Cobalt Strike's sleeve/beacon.x64.dll Versions 4.1 and 4.2"
		author = "gssincla@google.com"
		id = "dc320d17-98fc-5df3-ba05-4d134129317e"
		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#L1517-L1553"
		license_url = "https://github.com/chronicle/GCTI/blob/1c5fd42b1895098527fde00c2d9757edf6b303bb/LICENSE"
		hash = "29ec171300e8d2dad2e1ca2b77912caf0d5f9d1b633a81bb6534acb20a1574b2"
		logic_hash = "9b262ec18f79ab5ae63ad26d3685af088b5feb2d66de6ad3ba584cafbe2ee221"
		score = 75
		quality = 85
		tags = ""

	strings:
		$version_sig = { 83 F9 34 0F 87 8E 03 00 00 0F 84 7A 03 00 00 83 F9 1C 0F 87 E6 01 00 00
                     0F 84 D7 01 00 00 83 F9 0E 0F 87 E9 00 00 00 0F 84 CE 00 00 00 FF C9
                     0F 84 B8 00 00 00 83 E9 02 0F 84 9F 00 00 00 FF C9 }
		$decoder = { 80 34 28 ?? 48 FF C0 48 3D 00 10 00 00 7C F1 }

	condition:
		all of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$version_sighex{ 83 F9 34 0F 87 8E 03 00 00 0F 84 7A 03 00 00 83 F9 1C 0F 87 E6 01 00 00 0F 84 D7 01 00 00 83 F9 0E 0F 87 E9 00 00 00 0F 84 CE 00 00 00 FF …
$decoderhex{ 80 34 28 ?? 48 FF C0 48 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).

  • 29ec171300e8d2dad2e1ca2b77912caf0d5f9d1b633a81bb6534acb20a1574b2

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: dc320d17-98fc-5df3-ba05-4d134129317e

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