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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_RU_APT27_Hyperbro_Vftrace_Loader_Jan22_1

Yara rule to detect first Hyperbro Loader Stage, often called vftrace.dll. Detects decoding function.

APT / threat actorHyperbroSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Bundesamt fuer Verfassungsschutz (modified by Florian Roth)
Date
2022-01-14
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

Yara rule to detect first Hyperbro Loader Stage, often called vftrace.dll. Detects decoding function.

Associated malware family: Hyperbro.

Targets: Windows PE.

It defines 1 patterns (0 text, 1 hex, 0 regex). YARA modules used: pe.

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

Includes the imports needed to compile it on its own.

apt-ru-apt27-hyperbro-vftrace-loader-jan22-1.yarDetection Rule License 1.1
import "pe"

rule SIGNATURE_BASE_APT_RU_APT27_Hyperbro_Vftrace_Loader_Jan22_1 : FILE
{
	meta:
		description = "Yara rule to detect first Hyperbro Loader Stage, often called vftrace.dll. Detects decoding function."
		author = "Bundesamt fuer Verfassungsschutz (modified by Florian Roth)"
		id = "b049e163-2694-5fb9-a3a3-98cc77bcd0ca"
		date = "2022-01-14"
		modified = "2023-12-05"
		reference = "https://www.verfassungsschutz.de/SharedDocs/publikationen/DE/cyberabwehr/2022-01-bfv-cyber-brief.pdf"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_apt27_hyperbro.yar#L3-L19"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "333b52c2cfac56b86ee9d54aef4f0ff4144528917bc1aa1fe1613efc2318339a"
		logic_hash = "d8785ea937891636bea5ed8128de44fa6084a1a48800c1586739c5ca9e4c43bd"
		score = 75
		quality = 85
		tags = "FILE"
		sharing = "TLP:WHITE"

	strings:
		$decoder_routine = { 8A ?? 41 10 00 00 8B ?? 28 ?? ?? 4? 3B ?? 72 ?? }

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 5MB and $decoder_routine and pe.exports ( "D_C_Support_SetD_File" )
}

Strings (1 patterns)

IdentifierTypeValueModifiers
$decoder_routinehex{ 8A ?? 41 10 00 00 8B ?? 28 ?? ?? 4? 3B ?? 72 ?? }

Condition

uint16( 0 ) == 0x5a4d and filesize < 5MB and $decoder_routine and pe.exports ( "D_C_Support_SetD_File" )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 5MB (a cheap guard that skips large files).
  • Pattern $decoder_routine must be present.
  • Uses the pe module.
  • Checks exported functions or the DLL name.

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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).

  • 333b52c2cfac56b86ee9d54aef4f0ff4144528917bc1aa1fe1613efc2318339a

Licence & attribution

Author: Bundesamt fuer Verfassungsschutz (modified by Florian Roth)

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: b049e163-2694-5fb9-a3a3-98cc77bcd0ca

Metadata

sharingTLP:WHITE

Tags:FILE

Related rules

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