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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_APT29_NOBELIUM_Stageless_Loader_May21_2

Detects stageless loader as used by APT29 / NOBELIUM

APT / threat actorSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2021-05-29
Modified
2025-03-21
Score / Quality
75 / 85

What this rule detects

Detects stageless loader as used by APT29 / NOBELIUM

Targets: Windows PE.

It defines 6 patterns (4 text, 2 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
apt-apt29-nobelium-stageless-loader-may21-2.yarDetection Rule License 1.1
rule SIGNATURE_BASE_APT_APT29_NOBELIUM_Stageless_Loader_May21_2 : FILE
{
	meta:
		description = "Detects stageless loader as used by APT29 / NOBELIUM"
		author = "Florian Roth (Nextron Systems)"
		id = "7b83d327-52fc-5401-ae35-00f6b825678a"
		date = "2021-05-29"
		modified = "2025-03-21"
		reference = "https://www.microsoft.com/security/blog/2021/05/28/breaking-down-nobeliums-latest-early-stage-toolset/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_apt29_nobelium_may21.yar#L254-L276"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "a4f1f09a2b9bc87de90891da6c0fca28e2f88fd67034648060cef9862af9a3bf"
		hash = "c4ff632696ec6e406388e1d42421b3cd3b5f79dcb2df67e2022d961d5f5a9e78"
		logic_hash = "850f6a1ad342fd5e4bb29c7bf90a032ddd8ac9d2eac5ffcbedf43e4d04b178f5"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$x1 = "DLL_stageless.dll" ascii fullword
		$s1 = "c:\\users\\devuser\\documents" ascii fullword nocase
		$s2 = "VisualServiceComponent" ascii fullword
		$s3 = "CheckUpdteFrameJavaCurrentVersion" ascii fullword
		$op1 = { a3 d? 6? 04 10 ff d6 33 05 00 ?0 0? 10 68 d8 d4 00 10 57 a3 d? 6? 04 10 ff d6 33 05 00 ?0 0? 10 }
		$op2 = { ff d6 33 05 00 ?0 0? 10 68 d8 d4 00 10 57 a3 d? 6? 04 10 ff d6 33 05 00 ?0 0? 10 68 e8 d4 00 10 }

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 900KB and 2 of them or 3 of them
}

Strings (6 patterns)

IdentifierTypeValueModifiers
$x1text"DLL_stageless.dll"ascii fullword
$s1text"c:\\users\\devuser\\documents"ascii fullword nocase
$s2text"VisualServiceComponent"ascii fullword
$s3text"CheckUpdteFrameJavaCurrentVersion"ascii fullword
$op1hex{ a3 d? 6? 04 10 ff d6 33 05 00 ?0 0? 10 68 d8 d4 00 10 57 a3 d? 6? 04 10 ff d6 33 05 00 ?0 0? 10 }
$op2hex{ ff d6 33 05 00 ?0 0? 10 68 d8 d4 00 10 57 a3 d? 6? 04 10 ff d6 33 05 00 ?0 0? 10 68 e8 d4 00 10 }

Condition

uint16( 0 ) == 0x5a4d and filesize < 900KB and 2 of them or 3 of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 900KB (a cheap guard that skips large files).
  • At least 2 patterns in the rule must match.
  • At least 3 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).

  • a4f1f09a2b9bc87de90891da6c0fca28e2f88fd67034648060cef9862af9a3bf
  • c4ff632696ec6e406388e1d42421b3cd3b5f79dcb2df67e2022d961d5f5a9e78

Licence & attribution

Author: Florian Roth (Nextron Systems)

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: 7b83d327-52fc-5401-ae35-00f6b825678a

Tags:FILE

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