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GCTI_Cobaltstrike_Resources_Xor_Bin_V2_X_To_V4_X

Cobalt Strike's resource/xor.bin signature for version 2.x through 4.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 resource/xor.bin signature for version 2.x through 4.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-xor-bin-v2-x-to-v4-x.yarApache License 2.0
rule GCTI_Cobaltstrike_Resources_Xor_Bin_V2_X_To_V4_X
{
	meta:
		description = "Cobalt Strike's resource/xor.bin signature for version 2.x through 4.x"
		author = "gssincla@google.com"
		id = "1754746c-3a42-5f7d-808a-ba2e1c0a270e"
		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_Xor_Bin__32bit_v2_x_to_4_x.yara#L17-L36"
		license_url = "https://github.com/chronicle/GCTI/blob/1c5fd42b1895098527fde00c2d9757edf6b303bb/LICENSE"
		hash = "211ccc5d28b480760ec997ed88ab2fbc5c19420a3d34c1df7991e65642638a6f"
		logic_hash = "ad662a263ede6c3ba964baf8abe4848ed1e994f2c236d4315cb60c1d51442620"
		score = 75
		quality = 85
		tags = ""

	strings:
		$stub52 = {fc e8 ?? ?? ?? ?? [1-32] eb 27 5? 8b ??    83 c? ?4 8b ??    31 ?? 83 c? ?4 5? 8b ??    31 ?? 89 ??    31 ?? 83 c? ?4 83 e? ?4 31 ?? 39 ?? 74 ?2 eb ea 5? ff e? e8 d4 ff ff ff}
		$stub56 = {fc e8 ?? ?? ?? ?? [1-32] eb 2b 5d 8b ?? ?? 83 c5 ?4 8b ?? ?? 31 ?? 83 c5 ?4 55 8b ?? ?? 31 ?? 89 ?? ?? 31 ?? 83 c5 ?4 83 e? ?4 31 ?? 39 ?? 74 ?2 eb e8 5? ff e? e8 d? ff ff ff}

	condition:
		any of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$stub52hex{fc e8 ?? ?? ?? ?? [1-32] eb 27 5? 8b ?? 83 c? ?4 8b ?? 31 ?? 83 c? ?4 5? 8b ?? 31 ?? 89 ?? 31 ?? 83 c? ?4 83 e? ?4 31 ?? 39 ?? 74 ?2 eb ea 5? ff e? …
$stub56hex{fc e8 ?? ?? ?? ?? [1-32] eb 2b 5d 8b ?? ?? 83 c5 ?4 8b ?? ?? 31 ?? 83 c5 ?4 55 8b ?? ?? 31 ?? 89 ?? ?? 31 ?? 83 c5 ?4 83 e? ?4 31 ?? 39 ?? 74 ?2 eb e8 5? ff e? …

Condition

any of them

In plain words (Heuristic)

  • At least one pattern 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).

  • 211ccc5d28b480760ec997ed88ab2fbc5c19420a3d34c1df7991e65642638a6f

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: 1754746c-3a42-5f7d-808a-ba2e1c0a270e

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