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YARA · CAPE Sandbox (CAPEv2)

CAPE_Blister

Blister Loader

MalwareCAPE Sandbox (CAPEv2)GNU General Public License v3.0Compiles with YARA-X
Author
kevoreilly
Date
2022-05-10
Modified
2023-09-20
Score / Quality
75 / 70

What this rule detects

Blister Loader

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
blister.yarGNU General Public License v3.0
rule CAPE_Blister : FILE
{
	meta:
		description = "Blister Loader"
		author = "kevoreilly"
		id = "525fc600-2afc-5cf6-bf55-4ce0ea264dca"
		date = "2022-05-10"
		modified = "2023-09-20"
		reference = "https://github.com/kevoreilly/CAPEv2"
		source_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/data/yara/CAPE/Blister.yar#L1-L17"
		license_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/LICENSE"
		hash = "afb77617a4ca637614c429440c78da438e190dd1ca24dc78483aa731d80832c2"
		hash = "d3eab2a134e7bd3f2e8767a6285b38d19cd3df421e8af336a7852b74f194802c"
		logic_hash = "f26d85fdf0eb07e67fe38c43c5f6d024bfb7b2a333cb3411f5cdcff6bf5db12d"
		score = 75
		quality = 70
		tags = "FILE"
		cape_type = "Blister Loader"

	strings:
		$protect1 = {50 6A 20 8D 45 ?? 50 8D 45 ?? 50 6A FF FF D7}
		$protect2 = {48 83 C9 FF 48 8D 55 ?? FF D6 48 8D 87 [2] 00 00 48 8D 4D ?? FF D0}
		$lock1 = {B9 FF FF FF 7F 89 75 FC 8B C1 F0 FF 45 FC 83 E8 01 75}
		$lock2 = {B8 FF FF FF 7F 41 BC 01 00 00 00 89 45 40 F0 FF 4D 40 49 2B C4 75}
		$decode = {0F BE C0 49 03 CC 41 33 C1 44 69 C8 [4] 41 8B C1 C1 E8 0F 44 33 C8 8A 01 84 C0 75 E1 41 81 F9 [4] 74}

	condition:
		uint16( 0 ) == 0x5A4D and 2 of them
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$protect1hex{50 6A 20 8D 45 ?? 50 8D 45 ?? 50 6A FF FF D7}
$protect2hex{48 83 C9 FF 48 8D 55 ?? FF D6 48 8D 87 [2] 00 00 48 8D 4D ?? FF D0}
$lock1hex{B9 FF FF FF 7F 89 75 FC 8B C1 F0 FF 45 FC 83 E8 01 75}
$lock2hex{B8 FF FF FF 7F 41 BC 01 00 00 00 89 45 40 F0 FF 4D 40 49 2B C4 75}
$decodehex{0F BE C0 49 03 CC 41 33 C1 44 69 C8 [4] 41 8B C1 C1 E8 0F 44 33 C8 8A 01 84 C0 75 E1 41 81 F9 [4] 74}

Condition

uint16( 0 ) == 0x5A4D and 2 of them

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

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

  • afb77617a4ca637614c429440c78da438e190dd1ca24dc78483aa731d80832c2
  • d3eab2a134e7bd3f2e8767a6285b38d19cd3df421e8af336a7852b74f194802c

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: 525fc600-2afc-5cf6-bf55-4ce0ea264dca

Metadata

cape_typeBlister Loader

Tags:FILE

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