vucsa - 易受攻击的客户端-服务器应用程序(VuCSA)是

项目说明

! Client-Ser (VuCSA)

Client-Ser (VuCSA)

client-ser (VuCSA) is made for learning/presenting
how to perform penetration tests of non-http client-ser.
It is written in Java (with JavaFX graphical user interface).

Currently, the application contains the following challenges:

1. Buffer O (simulated)
2. Command Execution
3. SQL Injection
4. Enumeration
5. XML
6. Horizontal Access Control
7. Access Control
8. RCE Deserialization

If you want to know how to sol challenges, take a look at the PETEP website,
which describes how to use the open-source tool PETEP to exploit them.

Tip 1: Before you start hacking, do not forget to check the data structure of messages bellow.
When modifying the network traffic, you will probably have to consider the structure,
especially payload length bytes.

Tip 2: Most of the challenges can be exploited through modification of network traffic.
Therefore, it is recommended to use TCP proxy or process hooks for the testing.

Tip 3: Some challenges ha and restrictions in place, which is common in thick clients,
but it does not mean that the server uses the same .

Buffer O (simulated)

In this challenge, your goal is to manipulate the network traffic between the client and the server in a way
that leads to buffer o.

Command Execution

Command execution challenge represents a very simple command execution .
The goal is to execute malicious command on the server.

SQL Injection

SQL Injection challenge contains a search input to SQL injection,
but as you will soon notice, the input does not allow you to input the characters you need.

Enumeration

Enumeration challenge is based on simulated login form that is not protected from enumeration.
Will you be able to find all 5 users and guess their passwords?

XML

In this challenge, you can find multiple XML :

XML External Entity Attack (XXE Injection)

XInclude Attack

XML Bomb Attack

Horizontal Access Control

Horizontal Access Control challenge represents document reader that allows the user to see
own documents and read their content.
The goal is to find 5 documents of other users.

Access Control

Access Control challenge is based on simulated user panel, which shows basic user
information. The goal is to find a hidden admin functionality and check if it is possible
to use it as a Guest user.

RCE Deserialization

RCE Deserialization uses Ja/serialization for transmitting data through the network.
The application contains two paths that you can use to achie code execution through
the Ja.

You can find both paths by examining the server's JAR file
or by looking into the source code.

The goal is to create exploits for both paths and execute malicious command on the server.

Tip: You can use the server JAR as library to make the exploit creation easier.

Requirements

You need Java 11 or newer to run VuCSA.

*Note: For Mac with ARM64 architecture (M1, M2 chips), use special build for Java 17.*

How to Run

In order to run the server and client, you can use one of releases on GitHub
or run gradle assemble, which creates distribution packages (for both Windows and Unix).
These packages contain sh/bat scripts that will run the server and client using JVM:

*Note: These run scripts contain useful , including path to Ja.
You might need to change it if you do not have it in PATH or you use multiple Ja.*

Run Configuration

Ser is automatically created if it does not exist
and after that it is loaded from server.json in the same directory where the server is running:

Client configuration can be specified in the running application.

Project Structure

Project is divided into three modules:

- common functionality for both client and server (including protocol processing utilities)

- client with JavaFX GUI

- server for terminal use

Data Structure

Messages transmitted between server and client have the following simple format:

[type][target][length][payload]
32b 32b 32b ???

These four parts have the following meaning:

type - type of the message (used for serialization/deserialization)

target - target handler that will receive the message (identifier)

length - length of the payload

payload - data serialized into bytes

In order to send custom payloads, you might have to update the payload length.
Otherwise, it will not work properly. In the tutorial,
automatic script is de to auto-fix the payload length bytes.

Tutorial (Solutions)

client-ser (VuCSA) contains multiple ,
which can be exploited in ways. Official guide for exploiting these
uses open-source PEnetration TEsting Proxy (see PETEP Methodology).

In the PETEP methodology, the whole process of exploiting the challenges is explained,
including useful payloads.

项目信息

开发语言：Java

Star 数：103

技术要点

该项目属于CTF思路方向的开源资源，代码结构清晰，适合安全研究人员学习参考。项目围绕Vulnerable Client-Server Application (VuCSA) is made for learning how to perform penetration tests of non-http thick clients. It is written in Java (with JavaFX graphical user interface) and contains multiple challenges including SQL injection, RCE, XML vulnerabilities and more.展开，提供了可运行的实现，对理解相关安全机制、工具原理与攻防技术具有较高的研究价值。

从技术实现角度看，此类项目的核心在于对底层原理的深入理解与工程化落地。开发者在研究过程中可以结合官方文档与社区讨论，梳理项目的初始化流程、核心模块职责与数据流转，逐步掌握其中的技术细节与设计思路。

使用与学习建议

1. 下载源码压缩包，解压到本地环境。

2. 根据项目类型准备对应的运行环境与依赖。

3. 按照 README 中的步骤完成配置与部署。

4. 在隔离的测试环境中运行验证，避免影响生产系统。

免责声明

本资源来源于开源社区，仅供安全研究、技术学习与合法授权范围内的攻防演练使用，请勿用于任何非法或侵害他人权益的用途。使用本项目产生的一切后果由使用者自行承担。