SharPyShell - 用于C#网络应用程序的微小和混淆的ASP.NET webshell

作者:Sec-Labs | 发布时间:

项目地址

https://github.com/antonioCoco/SharPyShell

SharPyShell

1bb87d41d1005134

 

SharPyShell 是一个小巧且混淆的 ASP.NET webshel​​l,它执行加密通道接收的命令,在运行时将它们编译到内存中。

SharPyShell 仅支持在 .NET Framework >= 2.0 上运行的 C# Web 应用程序
atm 不支持 VB。

用法

python3 SharPyShell.py generate -p somepassword
python3 SharPyShell.py interact -u http://target.url/sharpyshell.aspx -p somepassword

要求

Python 版本 >= 3.6

pip3 install -r requirements.txt

描述

SharPyShell 是一个用 Python 编写的后开发框架,它能够:

  • 生成混淆后的webshel​​l(generate);
  • 模拟 windows 终端作为 webshel​​l 的交互(interact)。

该框架的主要目的是为渗透测试人员提供一系列工具,以便在对 IIS 网络服务器的利用成功后简化后利用阶段。

此工具并非旨在替代 C2 服务器的框架(即 Meterpreter、Empire、ecc..),但当您登陆到入站和出站连接非常有限的完全受限服务器时,应该使用此工具。
在此框架中,您将拥有在目标服务器的 cmd 后面键入时进行 privesc、网络发现和横向移动所需的所有工具。

此外,该框架旨在尽可能隐蔽地在内存中执行 c# 代码和 powershell 模块。

SharPyShell 中实施的混淆旨在规避文件签名和网络签名 ID。
为了规避网络签名,已经开发了一个完全加密的通道来发送命令和接收输出。
文件签名的规避是通过在负责运行时编译 c# 代码的预编译 dll 上使用反射来实现的。

技术图

使用 asciiflow.com 生成

+-------------------------------------------+                      +--------------------------------------------+
| SharPyShell Client (Local)                |                      | Target Server (Remote)                     |
+-------------------------------------------+   +--------------+   +--------------------------------------------+
|                                           |   |  Encrypted   |   |                                            |
|   +--------+-----------------^-----------<---->     HTTP     <---->-----------+-----------------^--------+    |
|            |                 |            |   |   Channel    |   |            |                 |             |
|            |4-Receive        |1-Send      |   +--------------+   |            |2-Receive        |3-Send       |
|            |                 |            |                      |            |                 |             |
|   +--------v-----------------+--------+   |                      |   +--------v-----------------+--------+    |
|   |              Module               |   |                      |   |           Webshell URL            |    |
|   +--------+-----------------^--------+   |                      |   +--------+-----------------^--------+    |
|   |        |Parse            |Generate|   |                      |   |        |Parse            |Generate|    |
|   | +------v------+   +------+------+ |   |                      |   | +------v------+   +------+------+ |    |
|   | |Base64 Resp  |   |Base64 Req   | |   |                      |   | |Base64 Req   |   |Base64 Resp  | |    |
|   | +------+------+   +------^------+ |   |                      |   | +------+------+   +------^------+ |    |
|   |        |Decode           |Encode  |   |                      |   |        |Decode           |Encode  |    |
|   | +------v------+   +------+------+ |   |                      |   | +------v------+   +------+------+ |    |
|   | |Xor/Aes Data |   |Xor/Aes Data | |   |                      |   | |Xor/Aes Data |   |Xor/Aes Data | |    |
|   | +------+------+   +------^------+ |   |                      |   | +------+------+   +------^------+ |    |
|   |        |Decrypt          |Encrypt |   |                      |   |        |Decrypt          |Encrypt |    |
|   | +------v------+   +------+------+ |   |                      |   | +------v------+   +------+------+ |    |
|   | |Response     |   |C# Code      | |   |                      |   | |C# Code      |   |Output       | |    |
|   | +------+------+   +------+------+ |   |                      |   | +------+------+   +------+------+ |    |
|   |        |                 ^        |   |                      |   |        |                 ^        |    |
|   |        v                 |        |   |                      |   |        v                 |        |    |
|   |        +--------+--------+        |   |                      |   |        +--------+--------+        |    |
|   |                 |                 |   |                      |   |                 |                 |    |
|   +---------------- ^ ----------------+   |                      |   +---------------- ^ ----------------+    |
|                     |                     |                      |                     |                      |
|                     |Run&Parse            |                      |                     |Compile&Run           |
|                     |                     |                      |                     |                      |
|             +------ v ------+             |                      |             +------ v ------+              |
|             |Terminal       |             |                      |             |csc.exe        |              |
|             +---------------+             |                      |             +---------------+              |
|             |Modules:       |             |                      |             |System.dll     |              |
|             |#exec_cmd      |             |                      |             |Compile in Mem |              |
|             |#exec_ps       |             |                      |             |No exe output  |              |
|             |#runas         |             |                      |             |               |              |
|             |.....          |             |                      |             |               |              |
|             |               |             |                      |             |               |              |
|             +---------------+             |                      |             +---------------+              |
|                                           |                      |                                            |
+-------------------------------------------+                      +--------------------------------------------+

模块

 #download               Download a file from the server                                            
 #exec_cmd               Run a cmd.exe /c command on the server                                     
 #exec_ps                Run a powershell.exe -nop -noni -enc 'base64command' on the server         
 #inject_dll_reflective  Inject a reflective DLL in a new (or existing) process                     
 #inject_dll_srdi        Inject a generic DLL in a new (or existing) process                        
 #inject_shellcode       Inject shellcode in a new (or existing) process                            
 #invoke_ps_module       Run a ps1 script on the target server                                      
 #invoke_ps_module_as    Run a ps1 script on the target server as a specific user                   
 #lateral_psexec         Run psexec binary to move laterally                                        
 #lateral_wmi            Run builtin WMI command to move laterally                                  
 #mimikatz               Run an offline version of mimikatz directly in memory                      
 #net_portscan           Run a port scan using regular sockets, based (pretty) loosely on nmap      
 #privesc_juicy_potato   Launch InMem Juicy Potato attack trying to impersonate NT AUTHORITY\SYSTEM 
 #privesc_powerup        Run Powerup module to assess all misconfiguration for privesc              
 #runas                  Run a cmd.exe /c command spawning a new process as a specific user         
 #runas_ps               Run a powershell.exe -enc spawning a new process as a specific user        
 #upload                 Upload a file to the server 

Windows版本测试

Windows 服务器 >= 2008 标准 x64

贡献

标签:工具分享, webshell绕过