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YARA · CAPE Sandbox (CAPEv2)

CAPE_Guloaderprecursor

Guloader precursor

GenericCAPE Sandbox (CAPEv2)GNU General Public License v3.0Compiles with YARA-X
Author
kevoreilly
Date
2020-12-29
Modified
2023-10-02
Score / Quality
75 / 70

What this rule detects

Guloader precursor

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
guloaderprecursor.yarGNU General Public License v3.0
rule CAPE_Guloaderprecursor : FILE
{
	meta:
		description = "Guloader precursor"
		author = "kevoreilly"
		id = "663f89d7-a18b-5b03-a7cb-52444a887fa4"
		date = "2020-12-29"
		modified = "2023-10-02"
		reference = "https://github.com/kevoreilly/CAPEv2"
		source_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/analyzer/windows/data/yara/Guloader.yar#L17-L28"
		license_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/LICENSE"
		logic_hash = "ea05c352739366a03da302074b01537382ba26f7fd5049004f156e47d284f070"
		score = 75
		quality = 70
		tags = "FILE"
		cape_options = "bp0=$antidbg,action0=scan,hc0=1,count=0"

	strings:
		$antidbg = {39 48 04 (0F 85 [3] ??|75 ??) 39 48 08 (0F 85 [3] ??|75 ??) 39 48 0C (0F 85 [3] ??|75 ??)}
		$except = {8B 45 08 [0-3] 8B 00 [0-3] 8B 58 18 [0-20] 81 38 05 00 00 C0 0F 85 [4-7] 83 FB 00 (0F 84|74)}

	condition:
		2 of them and not uint16( 0 ) == 0x5A4D
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$antidbghex{39 48 04 (0F 85 [3] ??|75 ??) 39 48 08 (0F 85 [3] ??|75 ??) 39 48 0C (0F 85 [3] ??|75 ??)}
$excepthex{8B 45 08 [0-3] 8B 00 [0-3] 8B 58 18 [0-20] 81 38 05 00 00 C0 0F 85 [4-7] 83 FB 00 (0F 84|74)}

Condition

2 of them and not uint16( 0 ) == 0x5A4D

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • At least 2 patterns in the rule must match.

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References

Licence & attribution

Author: kevoreilly

Source repository: CAPE Sandbox (CAPEv2) @ 6b15e76f28

Licence: GNU General Public License v3.0 (repository licence)

Copyright notice: Cuckoo Sandbox is copyrighted by the Cuckoo Foundation.

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: 663f89d7-a18b-5b03-a7cb-52444a887fa4

Metadata

cape_optionsbp0=$antidbg,action0=scan,hc0=1,count=0

Tags:FILE

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