Common Web Application Technologies

Introduction

Modern web applications are rarely built with a single technology. A typical application combines a web server, a programming language, a framework, a database, data formats, and backend services to deliver its functionality.

For anyone learning web application security, it’s important to understand these technologies at a basic level—not only to recognize them, but to understand where they sit in the architecture, how data moves through the system, and where weaknesses can be introduced.

This article covers:

1. Java Platform
2. ASP.NET
3. PHP
4. Ruby on Rails
5. SQL
6. XML
7. Web Services & SOAP

Web Application Architecture: The Big Picture

You can think of a web application as a pipeline:

User (Browser)
   ↓
Web Server / App Server
   ↓
Application Code
   ↓
Database / Backend Services
   ↓
Response back to Browser

A useful security question to keep in mind:

Once user input enters the application, where does it go, how is it processed, and is it handled safely?

1) The Java Platform (Enterprise Web Applications)

Java is widely used for large-scale enterprise applications. Java-based web apps can run on operating systems such as Windows, Linux, and Solaris and can use different application servers, frameworks, and third-party components.

Simplified Flow

Browser
   ↓
HTTP Request
   ↓
Java Web Container
   ↓
Java Application
   ↓
Database / Other Services
   ↓
HTTP Response

Common Java Terms (Quick Explanations)

Enterprise Java Bean (EJB)

An Enterprise Java Bean is a relatively heavyweight Java component that encapsulates the logic of a particular business function. It can also handle enterprise requirements such as transaction management.

Plain Old Java Object (POJO)

POJO stands for Plain Old Java Object—a regular Java object rather than a specialized component like an EJB. POJOs are typically simpler and more lightweight, which is why they are common in modern Java applications.

Java Servlet

A Java Servlet is a Java component that receives HTTP requests and returns HTTP responses. In many Java web stacks, servlets are central to request handling.

Java Web Container

A Java web container provides the runtime environment for Java web applications. Examples include:

• Apache Tomcat
• WebLogic
• JBoss

Third‑Party Components (Security Angle)

Java applications often rely on third‑party components for authentication, logging, ORM, and UI layers. For example:

Security note: a vulnerable dependency can affect the entire application, so dependency management and patching matter.

2) ASP.NET (.NET Web Framework)

ASP.NET is Microsoft’s web application framework for building applications on the .NET platform. Common languages include:

• C#
• VB.NET

Simplified Flow

Browser
   ↓
Web Server
   ↓
ASP.NET Application
   ↓
.NET Runtime
   ↓
Database / Backend Services

Event‑Driven Programming

ASP.NET supports an event-driven programming model. Example:

User clicks a button
        ↓
Button-click event
        ↓
Application code executes
        ↓
Action is performed

ASP.NET & Security

ASP.NET provides built-in mechanisms that help protect against certain common vulnerabilities (including some XSS-related defaults). However:

Secure Framework
       +
Insecure Application Logic
       =
Potentially Vulnerable Application

Framework features help, but secure design and implementation are still required.

3) PHP (Popular Server‑Side Technology)

PHP is a widely used server-side technology, especially in the open-source ecosystem.

LAMP Stack (Common Environment)

L → Linux   = Operating System
A → Apache  = Web Server
M → MySQL   = Database
P → PHP     = Programming Language

Simplified Flow

Browser
   ↓
Apache
   ↓
PHP Application
   ↓
MySQL

PHP & Security

PHP is relatively easy to learn, but security issues often appear when:

• input validation/encoding is weak
• configurations are insecure
• outdated frameworks or dependencies are used

Key takeaway: PHP itself is not “the vulnerability”—the implementation and configuration are what create risk.

4) Ruby on Rails (Rails Framework)

Ruby on Rails (Rails) is a web application framework built with the Ruby programming language. Rails follows the Model‑View‑Controller (MVC) architecture:

             Rails Application
                    │
        ┌───────────┼───────────┐
        ↓           ↓           ↓
      Model       View      Controller

• Model: handles data and database operations
• View: renders the UI/presentation layer
• Controller: handles requests and coordinates the flow between Model and View

Simplified Rails Flow

Browser
   ↓
Request
   ↓
Controller
   ↓
Model
   ↓
Database
   ↓
Controller
   ↓
View
   ↓
Response

Rails is known for conventions and automation, but security depends on:

• framework version
• gems/dependencies
• configuration
• application code quality

5) SQL (Structured Query Language)

SQL is used to access and manage data stored in relational databases such as MySQL, Oracle, and Microsoft SQL Server.

Example table:

users

+----+--------+------------------+
| id | name   | email            |
+----+--------+------------------+
| 1  | Rahul  | rahul@example.com|
| 2  | Amit   | amit@example.com |
+----+--------+------------------+

Example query:

SELECT email
FROM users
WHERE name = 'daf';

SQL & Security: SQL Injection

Web applications often include user input in database interactions:

User Input
    ↓
Web Application
    ↓
SQL Query
    ↓
Database

If untrusted input is handled unsafely when building or executing SQL queries, an attacker may be able to change the intended query—this is SQL Injection.

Key point: SQL is not the vulnerability. Unsafe handling of untrusted input is the vulnerability.

6) XML (Extensible Markup Language)

XML is a structured, machine-readable format used to represent and exchange data.

Example:

<user>
  <name>Rahul</name>
  <email>rahul@example.com</email>
</user>

In XML you’ll commonly see:

• elements/tags
• attributes (e.g., version="2.1")
• optional DTD rules that define structure and constraints

XML and XML-derived technologies are still common in enterprise systems, especially with SOAP.

7) Web Services & SOAP

A web service allows different applications or systems to communicate and exchange data or functionality.

SOAP (Simple Object Access Protocol) commonly uses:

HTTP → message transport
XML  → message format

SOAP message structure:

<soap:Envelope>
  <soap:Body>
    ...
  </soap:Body>
</soap:Envelope>

Web Services Security

In many architectures, the frontend is only an interface to an underlying web service:

User
 ↓
Frontend
 ↓
SOAP/XML
 ↓
Web Service
 ↓
Backend
 ↓
Database / Other Systems

Security testing should not stop at the UI. User-controlled data can travel through SOAP/XML requests into backend systems. If backend processing is insecure, vulnerabilities can occur (including SQL injection).

WSDL

SOAP services can be described using WSDL (Web Services Description Language). WSDL can document:

• services
• operations
• parameters
• data types
• endpoints

Tools such as soapUI can use a WSDL to help construct and send requests.

Final Takeaway

Java, ASP.NET, PHP, Ruby on Rails, SQL, XML, and SOAP are different technologies, but they often appear together within the same web application architecture.

For security learning (and testing), the best approach is:

1. Identify the technologies in use
2. Understand the architecture
3. Track data flow end-to-end
4. Validate how input is handled
5. Review dependencies and configuration

Ultimately, the key question is not “Which technology is this app using?” but:

How does the application process user data, and what security controls protect that data as it moves through the system?