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CAPE_Zloader_1

Zloader API Spam Bypass

GenericCAPE Sandbox (CAPEv2)GNU General Public License v3.0Compiles with YARA-X
Author
kevoreilly
Date
2021-03-12
Modified
2024-05-03
Score / Quality
75 / 70

What this rule detects

Zloader API Spam Bypass

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
zloader-1.yarGNU General Public License v3.0
rule CAPE_Zloader_1 : FILE
{
	meta:
		description = "Zloader API Spam Bypass"
		author = "kevoreilly"
		id = "8a8e7102-1138-59e7-95a6-8647d41d8521"
		date = "2021-03-12"
		modified = "2024-05-03"
		reference = "https://github.com/kevoreilly/CAPEv2"
		source_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/analyzer/windows/data/yara/Zloader.yar#L1-L12"
		license_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/LICENSE"
		logic_hash = "319adca805083c7f5854fe840447cf961addbd748f1f25eb8ec8cdeed7af38aa"
		score = 75
		quality = 70
		tags = "FILE"
		cape_options = "bp0=$trap1-5,action0=hooks:0,bp1=$traps-108,action1=jmp:15,bp2=$traps-88,action2=hooks:1,count=0"

	strings:
		$trap1 = {81 F7 4C 01 00 00 8D B4 37 [2] FF FF 31 FE 69 FE 95 03 00 00 E8 [4] 31 FE 0F AF FE 0F AF FE E8}
		$traps = {6A 44 53 E8 [2] FF FF 83 C4 08 8D 85 ?? FF FF FF C7 85 ?? FF FF FF 44 00 00 00 50}

	condition:
		uint16( 0 ) == 0x5A4D and any of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$trap1hex{81 F7 4C 01 00 00 8D B4 37 [2] FF FF 31 FE 69 FE 95 03 00 00 E8 [4] 31 FE 0F AF FE 0F AF FE E8}
$trapshex{6A 44 53 E8 [2] FF FF 83 C4 08 8D 85 ?? FF FF FF C7 85 ?? FF FF FF 44 00 00 00 50}

Condition

uint16( 0 ) == 0x5A4D and any of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • At least one pattern 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: 8a8e7102-1138-59e7-95a6-8647d41d8521

Metadata

cape_optionsbp0=$trap1-5,action0=hooks:0,bp1=$traps-108,action1=jmp:15,bp2=$traps-88,action2=hooks:1,count=0

Tags:FILE

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