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YARA · CAPE Sandbox (CAPEv2)

CAPE_Blister_1

Blister Sleep Bypass

GenericCAPE Sandbox (CAPEv2)GNU General Public License v3.0Compiles with YARA-X
Author
kevoreilly
Date
2022-05-10
Modified
2024-05-09
Score / Quality
75 / 70

What this rule detects

Blister Sleep Bypass

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-1.yarGNU General Public License v3.0
rule CAPE_Blister_1 : FILE
{
	meta:
		description = "Blister Sleep Bypass"
		author = "kevoreilly"
		id = "34657bab-f100-5ea8-9111-da2806f46b79"
		date = "2022-05-10"
		modified = "2024-05-09"
		reference = "https://github.com/kevoreilly/CAPEv2"
		source_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/analyzer/windows/data/yara/Blister.yar#L1-L17"
		license_url = "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/LICENSE"
		logic_hash = "aba379b93c85241cf250829832b2c8a5eaafb3abd0ff955dbaf0d06489c00deb"
		score = 75
		quality = 70
		tags = "FILE"
		cape_options = "bp0=$sleep1+6,bp1=$sleep2+7,action0=setsignflag,action1=clearcarryflag,count=3"
		packed = "0a7778cf6f9a1bd894e89f282f2e40f9d6c9cd4b72be97328e681fe32a1b1a00"
		packed = "afb77617a4ca637614c429440c78da438e190dd1ca24dc78483aa731d80832c2"

	strings:
		$sleep1 = {FF FF 83 7D F0 00 (E9|0F 8?)}
		$sleep2 = {81 7D D8 90 B2 08 00 (E9|0F 8?)}
		$protect = {50 6A 20 8D 45 ?? 50 8D 45 ?? 50 6A FF FF D7}
		$lock = {56 33 F6 B9 FF FF FF 7F 89 75 FC 8B C1 F0 FF 45 FC 83 E8 01 75 F7}
		$comp = {6A 04 59 A1 [4] 8B 78 04 8B 75 08 33 C0 F3 A7 75 0B 8B 45 0C 83 20 00 33 C0 40 EB 02 33 C0}

	condition:
		uint16( 0 ) == 0x5A4D and 2 of ( $protect , $lock , $comp ) and all of ( $sleep* )
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$sleep1hex{FF FF 83 7D F0 00 (E9|0F 8?)}
$sleep2hex{81 7D D8 90 B2 08 00 (E9|0F 8?)}
$protecthex{50 6A 20 8D 45 ?? 50 8D 45 ?? 50 6A FF FF D7}
$lockhex{56 33 F6 B9 FF FF FF 7F 89 75 FC 8B C1 F0 FF 45 FC 83 E8 01 75 F7}
$comphex{6A 04 59 A1 [4] 8B 78 04 8B 75 08 33 C0 F3 A7 75 0B 8B 45 0C 83 20 00 33 C0 40 EB 02 33 C0}

Condition

uint16( 0 ) == 0x5A4D and 2 of ( $protect , $lock , $comp ) and all of ( $sleep* )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in ( $sleep* ) must match.
  • At least 2 patterns in ( $protect , $lock , $comp ) 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: 34657bab-f100-5ea8-9111-da2806f46b79

Metadata

cape_optionsbp0=$sleep1+6,bp1=$sleep2+7,action0=setsignflag,action1=clearcarryflag,count=3
packed0a7778cf6f9a1bd894e89f282f2e40f9d6c9cd4b72be97328e681fe32a1b1a00
packedafb77617a4ca637614c429440c78da438e190dd1ca24dc78483aa731d80832c2

Tags:FILE

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