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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_EXT_NK_GOLDBACKDOOR_Injected_Shellcode

Detection for injected shellcode that decodes GOLDBACKDOOR

GenericSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Silas Cutler (silas@Stairwell.com)
Date
2022-04-21
Modified
2023-12-05
Score / Quality
80 / 85

What this rule detects

Detection for injected shellcode that decodes GOLDBACKDOOR

It defines 5 patterns (1 text, 4 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
ext-nk-goldbackdoor-injected-shellcode.yarDetection Rule License 1.1
rule SIGNATURE_BASE_EXT_NK_GOLDBACKDOOR_Injected_Shellcode
{
	meta:
		description = "Detection for injected shellcode that decodes GOLDBACKDOOR"
		author = "Silas Cutler (silas@Stairwell.com)"
		id = "aa921f01-98cc-51ab-877a-e7beede77e36"
		date = "2022-04-21"
		modified = "2023-12-05"
		reference = "https://stairwell.com/wp-content/uploads/2022/04/Stairwell-threat-report-The-ink-stained-trail-of-GOLDBACKDOOR.pdf"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_nk_goldbackdoor.yar#L22-L42"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "b45f408c0f342591e66ef0dfcfc1c09f8558c5e8f4bd7f824b30f00d531c7511"
		score = 80
		quality = 85
		tags = ""
		version = "0.1"

	strings:
		$dec_routine = { 8A 19 57 8B FA 8B 51 01 83 C1 05 85 D2 74 0E 56 8B C1 8B F2 30 18 40 83 EE 01 75 F8 5E 57 }
		$rtlfillmemory_load = { B9 4B 17 CD 5B 55 56 33 ED 55 6A 10 50 E8 86 00 00 00 FF D0 }
		$ = "StartModule"
		$log_file_name = { C7 44 24 3C 25 6C 6F 63 50 8D 44 24 40 C7 44 24 44 61 6C 
                           61 70 50 B9 BD 88 17 75 C7 44 24 4C 70 64 61 74 C7 44 24 
                           50 61 25 5C 6C C7 44 24 54 6F 67 5F 67 C7 44 24 58 6F 6C
                           64 32 C7 44 24 5C 2E 74 78 74 }
		$ = { B9 8E 8A DD 8D 8B F0 E8 E9 FB FF FF FF D0 }

	condition:
		3 of them
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$dec_routinehex{ 8A 19 57 8B FA 8B 51 01 83 C1 05 85 D2 74 0E 56 8B C1 8B F2 30 18 40 83 EE 01 75 F8 5E 57 }
$rtlfillmemory_loadhex{ B9 4B 17 CD 5B 55 56 33 ED 55 6A 10 50 E8 86 00 00 00 FF D0 }
$text"StartModule"
$log_file_namehex{ C7 44 24 3C 25 6C 6F 63 50 8D 44 24 40 C7 44 24 44 61 6C 61 70 50 B9 BD 88 17 75 C7 44 24 4C 70 64 61 74 C7 44 24 …
$hex{ B9 8E 8A DD 8D 8B F0 E8 E9 FB FF FF FF D0 }

Condition

3 of them

In plain words (Heuristic)

  • At least 3 patterns in the rule must match.

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References

Licence & attribution

Author: Silas Cutler (silas@Stairwell.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: aa921f01-98cc-51ab-877a-e7beede77e36

Metadata

version0.1

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