Software Security Testing Part — II

Update: This article is part of a series. Check out the full series: Part 1, Part 2, Part 3, Part 4, Part 5!


Welcome to the second module of the software security testing workshop. In this module, we will be exploring different types of evaluating software security. It is recommended that you should first complete the previous module in order to build a knowledge base in this domain, which will help you continue in this workshop with a separate mindset on how to be an expert in software security testing.

Software Security Testing

Different organizations and different security professionals define it differently and mostly all are correct. There are different ways of understanding software security testing. Following are some well-known concepts:

“Security testing which is non-functional in nature, more focused on security aspects”


“It is a type of testing in which a security professional performs different types of attacks to check the security blueprint of the software in order to find if the software or application is secure or not”


“It is also defined as a process in which security professionals determine that the overall information system integrated with the software is secure and protects data and maintains functionality as intended”

Core Values

The core concept that is considered while performing security testing of software is to cover the following as the major topics:

* Confidentiality

* Integrity

* Authentication

* Authorization

* Non-repudiation

* Availability

Considering the above six aspects in software security testing assures an improved software or application risk management for the enterprise. The purpose of security testing for flaws in software is to seek solutions to remove vulnerabilities before the software is purchased or deployed in the enterprise and, most importantly, to ensure security before the flaws can be exploited.

However, most enterprises think that software security testing can be problematic while considering the purchasing, installing, maintaining, and hiring internal security experts to operate it can be costly. And the time it takes to execute can impact productivity by slowing secure software development.

This is just one of the many reasons why leading enterprises have chosen automated, software security testing services from different vendors.

Types of Software Security Testing

With the different types of security testing that are usually performed by organizations, we can simply categorize them into the three main types as follows:

1. Front End Testing

2. End to End Testing

3. Main Code Testing

These types explain what type of testing is usually covered while they are performed. However, we will explain each one of them separately.

Front End Testing (FET)

This is basically testing of the front end of the software or application, focusing on the some of key aspects of the security lifecycle, and this type of testing doesn’t provide a high level of security as only the front end of the application is testing for security. FET is usually performed as a part of the overall security development lifecycle and it is not the recommended type of security testing that enterprises should follow. What it mainly covers is given below:

* Input validation

* SQL Injections

* Cross-site scripting

* Operational testing

* Segregation of duties

* Authentication mechanism of application

* Client-side environment of the application

These are some of the key activities that form an integral part of front-end testing (FET).

End-to-End Testing (E2E)

This is the most effective type of software security testing in which complete security assessment is performed, covering a range of security controls. Key activities that form the core of E2E are given below:

* Process Review of related software activities

* Segregation of Duties

* Workflow reviews

* Security Administration

* Roles and Responsibilities

* Core source code review

* Input validation

* SQL Injections

* Cross-Site scripting

* Authentication & authorization

* Backend database security

* Software dependencies check

* Vulnerabilities assessment

* Security misconfiguration

Main Code Testing (MCoT)

This type of testing is mostly used with different security testing tools which security professionals utilize for the detection of software weaknesses. This type is further divided into sub-divisions, based on the nature of testing for performing main code testing. These types are listed below:

* Quick code review

* Structural analysis review

* Complete code review

Quick code review is the baseline code review that runs if you do not select a code review in any set preference. It includes rules with the severity levels.

Structural analysis review is based on only an architectural review of the code and doesn’t cover an end-to-end review of the code to highlight all weaknesses.

Complete code review ensures all possible aspects of the weaknesses that should be considered in the review. The purpose is to ensure that no security holes are left in the software code before the software goes live in the industry. This is the most extensive type of code review that takes time and requires experienced security professionals with a strong background in programming and software development lifecycle.

Now, regardless of which MCoT type you use for performing security code review, there are two main methods that are supposed to be used to run this testing. These methods are basically based on which techniques security professionals use to achieve the goal.

Techniques or Methodologies

Two main techniques widely used in performing software code reviews are as follows:

* Black Box Method

* White Box Method

Now, you might have already guessed what the difference is between these two types, it is basically based on the approach. The Black Box method is better because it saves time and also uses parts of the White Box method in it.

Black Box Method

In this approach, the secure code review is done using different open testing tools commercially available or on an open source platform.

Quality assurance professionals use such tools during the development stage of the software but a security analyst also get help from them. These security tools are very useful while doing code reviews in order to analyze a large amount of main code, which is normally millions of lines of code.

They can quickly identify potentially insecure pieces of code in the main code, which can be further analyzed by the developer or a security professional with manual methods.

White Box Method

In this method, a thorough code review is performed over the whole code manually, which may become a very tedious and tiring process. However, this process might be helpful in identifying flaws but this requires at least more than two professionals in performing this type of code review.

The best way of performing this type of testing would be to concentrate on potential problems in the code instead of going line by line through the whole main code. Those potential vulnerabilities can be given a high priority.


In C/C++, we try to find any copying function in the code and check whether it’s using functions, such as strcpy() for performing copy function. As we know, strcpy() is vulnerable to buffer overflow attacks.


We may also want to check if any customized encryption is being used in the application, which automated tools may miss, as they can identify standard algorithms only.

By knowing these two methods, we see that the best approach will be a mix of both, depending on the volume and criticality of data. In today’s world, where many complex applications are developed, we can’t ignore any of the above-mentioned techniques.

However, it is recommended that Black Box is used first, and then later, perform some manual analysis on areas of code that are highlighted by the tools. For such manual reviews, a second security professional should be deployed in order to get the best results out of these methods.

Security Code Review Tools

There are many tools available in the market for performing security code reviews and these tools are based and dependent on the computer programming language in which the software is coded. You may find tools that have the capability to perform security reviews in more than one language and are considered leading software in performing code analysis. We have listed a few tools below, that you can download and try with the trial version. However, they may not all be available for free download and use


* Black Duck Suite

* Cigital SecureAssist

* Coverity SAVE

* HP Fortify Static Code Analyzer

* IBM Rational Appscan Source Edition

* Veracode SAST * Flawfinder

* Source code validation tool by cert

* Microsoft Code Analysis Tool (CAT.NET)

In our upcoming module, we will be utilizing the CAT.NET tool by Microsoft to perform the code review for .Net application. For this, you will be required to download a sample code and prepare to perform a security source code review of the application.

We will be talking in detail about the code review tools and the techniques further in our next module. In order to continue the workshop and gain practical experience in performing security code review, keep going through the workshop, as this is one of the very unique skills, not all security professionals possess. By completing this workshop, you will be able to execute source code reviews for at least .NET based applications or software.

Originally published at



Cyber Security Analyst & researcher

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