In a client-server architecture or network, a thick client (also known as a fat client) often offers robust capability without relying on the server. The majority of the processing in these applications is carried out on the client side.

Desktop applications, also known as “thick client” applications, are fully functional PCs that are networked. Thick clients are functional whether they are connected to a network or not, in contrast to thin clients, which lack hard drives and other functionality.

A thick client is completely functioning even when not connected to the internet, but it is only a “client” when it is. Programs and files that are not kept on the local machine’s hard drive could be made available to the thick client by the server.

In other words, it is a networked computer with a local installation of the majority of the resources. In fact, most thick clients may be utilized offline, that is, when not connected to a network or server, and have their own operating system and software programs.

Thick client apps have been used for many years and are still utilized by a wide range of businesses of all shapes and sizes. Thin-client apps may become a more attractive target for attackers as a result of the development of hybrid infrastructure architectures.

What is Thick Client Application Vulnerability Assessment?

Thick client application security describes the steps required to safeguard thick client applications, which are computer or device software applications that run on end users’ computers or other devices and demand a lot of resources and processing power. These programs frequently work with sensitive data and are open to many forms of assault, such as malware, phishing, and hacking.

Application layer vulnerabilities are common, and some of them may be serious enough to expose consumer data or undermine a system. Instead of merely concentrating on managing the application server, the IT staff must maintain and upgrade all systems for software deployment in order to preserve a thick client.

When performing internal audits and valuing security, corporations usually ignore thick client/fat client applications. Thick client evaluations are a difficult task, but many firms do not have enough internal security professionals who are equipped with the necessary knowledge and experience.

Thick Client Penetration Testing: What Is It?

A client program that can offer rich functionality without relying on the server in a network is referred to as a “thick client,” also known as a “fat client.” The majority of thick client operations can be carried out without an active server connection. While they do occasionally need to connect to a network on the central server, they can operate independently and may contain locally stored resources.

On the other hand, a “thin client” is a client program or computer that requires a connection to the server in order to work. Thin clients rely heavily on server access each time they need to analyze or validate input data because they perform as little processing on their own as is feasible.

Two-Tier and Three-Tier Thick Clients

Thick clients can be found in network architectures with two or three tiers. Due to its multi-tiered or multi-level design, the client/server paradigm of networks is also known as the tiered model.

The client app talks with the server through an application server in a three-tier architecture.

The presentation tier, the application tier, and the data tier are the three layers that make up this model. The presentation tier serves as the interface through which the end user interacts with the application; the application tier processes the data gathered in the presentation tier; and the data tier stores and manages the processed data.

In a two-tier design, the thick client application interfaces directly with the server. The presentation tier and the data tier make up this model. It is a less secure network design than the three-tier approach since the end user has direct access to the data tier.

Why do thick client applications need testing?

For internal operations, thick client applications are crucial. They are frequently used to interact with private data, such as financial and health records, and they provide a significant danger to a business, particularly if they are legacy applications.

Thick clients function differently, and each has advantages and disadvantages of their own. The security that thin clients offer over thick clients is one of their main advantages.  The following are some of the main security issues with thick clients:

  • Sensitive data disclosure.
  • Denial of Service (DoS).
  • Improper access control.
  • Improper session management.
  • Reverse engineering.
  • Injection attacks.
  • Variable and response manipulation.
  • Improper error handling.
  • Insecure storage.

How can thick client apps be tested?

Thick client applications require a certain strategy when it comes to a penetration test because they are typically more involved and customized than online or mobile applications.

When dealing with a thick client application, the initial step is to obtain data, such as:

  • Identifying the technologies being utilized on both the server and client sides.
  • Determining the behavior and operation of the program.
  • Locating all of the various user input entry locations.
  • Recognizing the application’s primary security techniques.
  • Recognizing widespread vulnerabilities in things like languages and frameworks.

Phases of Thick Client Application Vulnerability Assessment & Penetration Testing

  1. Mapping and Scoping

Make a business process model and agree to it. By identifying and regulating access to documents and information, scoping ensures their security. It makes it possible to map out the problems for subsequent steps. A brief meeting with the client will be required as part of this process to review and confirm the rules of engagement for penetration testing as well as to establish the project scope and testing schedule.

2. Enumeration and Information Gathering

The tester receives information from this stage that can be used to find and take advantage of vulnerabilities in the online applications. This phase’s objective is to detect any sensitive data, such as application technology, usernames, version information, hardcoded data, etc., that may be useful during the testing phases that follow.

3. Scanning

To identify recurring problems in the thick client software, we employ a proprietary method. For our experts to investigate, the tool also lists the thick client’s network communication, interprocess communication, operating system interactions, and other activities.

4. Vulnerability identification and assessment

The list of all targets and apps that fall under the scope of the vulnerability analysis phase will be compiled at both the network layer and the application layer. Our experts examine the setup of your thick client, detecting both issues with the default configuration and potential methods the application could be set up to avoid security measures.

5. Exploitation

All potential vulnerabilities found in the earlier stages of the assessment will be subjected to this phase’s effort to exploit them like an attacker would. Business logic problems, bypasses for authentication and authorization, direct object references, parameter manipulation, and session management are all included in this. The majority of thick clients make use of some server-side capability, and all thick clients or central data storage may be impacted by a server-side vulnerability that is successfully exploited.

Need Penetration Testing for Thick Client Applications?

Regardless of whether your thick client application is hosted internally or in a virtualized environment, Elanus Technologies evaluates it. When conducting security assessments for thick client applications, we look at best practices for authorization and authentication as well as data storage and communication pathways. To assess your application, we use manual and automated pen-testing procedures using paid, free, and open-source cybersecurity.

We at Elanus Technologies specialize in thick client application security, including:

  • Static Analysis: To find potential flaws and vulnerabilities in the application’s source code without actually running it, our professionals use cutting-edge methods.
  • Dynamic analysis: To find any flaws or weaknesses in the functionality of the application, our specialists run the application and examine its behavior while it operates.
  • Penetration testing: During this process, we mimic a real-world assault on the application in order to find and exploit vulnerabilities and provide a comprehensive evaluation of its security posture.
  • Review of Configuration: Our team of specialists examines the configuration of the application and suggests modifications to increase the application’s general security.
  • Network Traffic Analysis: To discover and reduce potential security concerns, our professionals track and examine network traffic. Security Code Review: Our team of professionals examines the application’s source code for security flaws, finding any potential problems and offering solutions.

Get in touch with us for more insights.