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YARA · CAPE Sandbox (CAPEv2)

CAPE_Nitrobunnydownloader

NitroBunnyDownloader

GenericCAPE Sandbox (CAPEv2)GNU General Public License v3.0Compiles with YARA-X
Author
enzok
Date
2025-10-28
Modified
2025-11-05
Score / Quality
75 / 70

What this rule detects

NitroBunnyDownloader

Targets: Windows PE.

It defines 7 patterns (5 text, 2 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

nitrobunnydownloader.yarGNU General Public License v3.0
rule CAPE_Nitrobunnydownloader : FILE
{
	meta:
		description = "NitroBunnyDownloader"
		author = "enzok"
		id = "64faa91a-4847-57bd-ab71-27029f6074ac"
		date = "2025-10-28"
		modified = "2025-11-05"
		reference = "https://github.com/kevoreilly/CAPEv2"
		source_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/data/yara/CAPE/NitroBunnyDownloader.yar#L1-L18"
		license_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/LICENSE"
		hash = "960e59200ec0a4b5fb3b44e6da763f5fec4092997975140797d4eec491de411b"
		logic_hash = "dcc1348c1d1af0c854376cf6331538951362b43d8d76c0ad73bbbdeb1ab4c135"
		score = 75
		quality = 70
		tags = "FILE"
		cape_type = "NitroBunnyDownloader Payload"

	strings:
		$config1 = {E8 [3] 00 41 B8 ?? ?? 00 00 48 8D 15 [3] 00 48 89 C1 48 89 ?? E8 [3] 00}
		$config2 = {E8 [3] 00 48 8D 15 [3] 00 41 B8 ?? ?? 00 00 48 89 C1 48 89 ?? E8 [3] 00}
		$string1 = "X-Amz-User-Agent:" wide
		$string2 = "Amz-Security-Flag:" wide
		$string3 = "/cart" wide
		$string4 = "Cookie: " wide
		$string5 = "wishlist" wide

	condition:
		uint16( 0 ) == 0x5A4D and 1 of ( $config* ) and 2 of ( $string* )
}

Strings (7 patterns)

IdentifierTypeValueModifiers
$config1hex{E8 [3] 00 41 B8 ?? ?? 00 00 48 8D 15 [3] 00 48 89 C1 48 89 ?? E8 [3] 00}
$config2hex{E8 [3] 00 48 8D 15 [3] 00 41 B8 ?? ?? 00 00 48 89 C1 48 89 ?? E8 [3] 00}
$string1text"X-Amz-User-Agent:"wide
$string2text"Amz-Security-Flag:"wide
$string3text"/cart"wide
$string4text"Cookie: "wide
$string5text"wishlist"wide

Condition

uint16( 0 ) == 0x5A4D and 1 of ( $config* ) and 2 of ( $string* )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • At least 1 patterns in ( $config* ) must match.
  • At least 2 patterns in ( $string* ) 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).

  • 960e59200ec0a4b5fb3b44e6da763f5fec4092997975140797d4eec491de411b

Licence & attribution

Author: enzok

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: 64faa91a-4847-57bd-ab71-27029f6074ac

Metadata

cape_typeNitroBunnyDownloader Payload

Tags:FILE