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GCTI_Cobaltstrike_Resources_Reverse64_Bin_V2_5_Through_V4_X

Cobalt Strike's resources/reverse64.bin signature for versions v2.5 to v4.x

Hack toolCobalt StrikeGoogle Cloud Threat Intelligence (GCTI)Apache License 2.0Compiles with YARA-X
Author
gssincla@google.com
Date
2022-11-18
Modified
2022-11-19
Score / Quality
75 / 85

What this rule detects

Cobalt Strike's resources/reverse64.bin signature for versions v2.5 to v4.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-reverse64-bin-v2-5-through-v4-x.yarApache License 2.0
rule GCTI_Cobaltstrike_Resources_Reverse64_Bin_V2_5_Through_V4_X
{
	meta:
		description = "Cobalt Strike's resources/reverse64.bin signature for versions v2.5 to v4.x"
		author = "gssincla@google.com"
		id = "966e6e4c-85e2-5c94-8245-25367802b7d2"
		date = "2022-11-18"
		modified = "2022-11-19"
		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_Reverse64_Bin_v2_5_through_v4_x.yara#L17-L99"
		license_url = "https://github.com/chronicle/GCTI/blob/1c5fd42b1895098527fde00c2d9757edf6b303bb/LICENSE"
		hash = "d2958138c1b7ef681a63865ec4a57b0c75cc76896bf87b21c415b7ec860397e8"
		logic_hash = "c657234156293b9ac363b677490739ab0b5cc2ef149c9d9c37332dab9bb012f6"
		score = 75
		quality = 85
		tags = ""

	strings:
		$apiLocator = {
			48 [2]
			AC
			41 [2] 0D
			41 [2]
			38 ??
			75 ??
			4C [4]
			45 [2]
			75 ??
			5?
			44 [2] 24
			49 [2]
			66 [4]
			44 [2] 1C
			49 [2]
			41 [3]
			48 
		}
		$calls = {
			48 89 C1
			41 BA EA 0F DF E0
			FF D5
			48 [2]
			6A ??
			41 ??
			4C [2]
			48 [2]
			41 BA 99 A5 74 61
			FF D5
		}

	condition:
		$apiLocator and $calls
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$apiLocatorhex{ 48 [2] AC 41 [2] 0D 41 [2] 38 ?? 75 ?? 4C [4] 45 [2] 75 ?? 5? 44 [2] 24 49 [2] 66 [4] 44 [2] 1C 49 [2] 41 [3] …
$callshex{ 48 89 C1 41 BA EA 0F DF E0 FF D5 48 [2] 6A ?? 41 ?? 4C [2] 48 [2] 41 BA 99 A5 74 61 FF D5 }

Condition

$apiLocator and $calls

In plain words (Heuristic)

  • Pattern $apiLocator must be present.
  • Pattern $calls 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).

  • d2958138c1b7ef681a63865ec4a57b0c75cc76896bf87b21c415b7ec860397e8

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: 966e6e4c-85e2-5c94-8245-25367802b7d2

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