Thick clients fall into two categories: Two-Tier Thick Clients and Three-Tier thick clients:
Two-Tier Thick Client Application:
Imagine you have a simple computer program that you use to manage your personal tasks and to-do lists. In a two-tier thick client application, the program’s functionality is divided into two main parts:
Frontend (Client): This is the part of the program that you interact with directly on your computer. It provides a user interface where you can add, edit, and view your tasks. When you use the program, it runs on your computer, and you can work with it even if you’re not connected to the internet. The client part handles all the tasks related to displaying the user interface and processing your interactions with the application. Backend (Server): In this case, the backend is usually a local database or file system on your computer. It stores all your task-related data, such as the task names, descriptions, due dates, etc. The backend part of the application is responsible for managing this data and making sure it’s stored securely on your computer.
So, in a two-tier thick client application, the entire program runs on your computer, and both the frontend and backend components are handled locally.
Three-Tier Thick Client Application:
Now, let’s expand on the previous example and add a new layer to the application:
Frontend (Client): This remains the same as in the two-tier application. It’s the part you directly interact with on your computer, allowing you to manage your tasks and to-do lists.
Middle Tier (Application Server): In a three-tier thick client application, we introduce a middle tier, which acts as a bridge between the frontend and the backend. The middle tier runs on a separate server, either on your local network or on the internet. Its role is to handle the business logic of the application, such as managing task data, user authentication, and processing various operations. When you interact with the frontend, the requests are sent to the middle tier, which processes them and communicates with the backend to retrieve or store data.
Backend (Database Server): This is similar to the backend in the two-tier application. The backend is a dedicated server or database system that stores all the task-related data securely. It communicates with the middle tier to retrieve or store data as needed.
In a three-tier thick client application, the frontend and middle tier communicate over the network, and the backend stores the data on a separate server. This architecture allows for more scalability and separation of concerns, making it easier to manage and maintain the application as it grows.
In summary, a two-tier thick client application has the frontend and backend running on the user’s computer, while a three-tier thick client application adds a middle tier that acts as a mediator between the frontend and the backend, running on a separate server.
The process of Thick Client Penetration Testing typically involves the following steps:
Installation and Setup: The penetration tester sets up a controlled environment with the thick client application installed on a virtual machine or a dedicated testing system. They may also use network capture tools to analyze network traffic generated by the application during its use.
Reconnaissance: The tester examines the thick client application to gather information about its functionalities, interactions with the server, communication protocols used, and other relevant details. This step may involve reverse engineering to understand how the application processes data and communicates with the server.
Traffic Analysis: The tester captures and analyzes the network traffic generated by the thick client application during various interactions with the server. This analysis helps in identifying potential security flaws, sensitive data transmission, and possible vulnerabilities related to network communications.
Static Analysis: The tester may perform static analysis of the thick client application’s executable files to identify potential vulnerabilities, such as hardcoded credentials, insecure storage of sensitive data, or other security-related issues within the application’s code.
Dynamic Analysis: The thick client application is run in a controlled environment, and the tester performs various interactions with the application to understand its behavior and identify vulnerabilities in real-time. This may include input validation testing, error handling testing, and boundary testing to discover potential weaknesses.
Memory Analysis: Memory analysis techniques are applied to the thick client application to identify potential security issues related to memory handling, such as buffer overflows or other memory-related vulnerabilities.
Privilege Escalation: The tester attempts to escalate privileges within the thick client application or the underlying operating system to assess whether unauthorized access or control can be achieved.
Data Storage Assessment: The tester examines how the thick client application stores sensitive data on the client side, looking for insecure storage practices that could expose sensitive information to potential attackers.
Reporting: The results of the Thick Client Penetration Testing are documented in a comprehensive report. The report includes identified vulnerabilities, their severity level, potential impact, and recommended remediation steps to address the issues.
Remediation and Re-testing: Once the thick client application owner or development team receives the report, they work to fix the identified vulnerabilities.
Thick Client Penetration Testing is crucial for ensuring the security of applications running on end-user machines, especially when they handle sensitive data or have privileged access to critical systems. By identifying and addressing vulnerabilities proactively, organizations can enhance the overall security posture of their thick client applications and protect against potential cyber threats.
Recommendation for pricing: Depending on the scope, difficulty, time, and expertise related to thick client penetration testing, the price can vary. At Hackybara, we would recommend pricing for Thick client penetration testing based on the options below:
Two-Tier Application: $500
Three-Tier Application: $1000
Recommend time range: 1-2 weeks (not including time spent if a business requires a background check)
