Faced with an ever-increasing number of sophisticated attacks, web application security is a major challenge. Indeed, security is now crucial to reassure customers, build loyalty and convert prospects.

There are several ways of assessing the security of a web application. In this article, we present the “offensive” approach, which we believe to be the most effective: web application penetration testing. We detail the principles and objectives, as well as use cases for black box, grey box and white box penetration tests on various targets.

In a previous article, we reviewed the most critical and widespread vulnerability in web applications according to the OWASP Top 10: broken access control. Today, we tackle the common vulnerabilities and exploits related to the lack or absence of encryption in applications.

The Open Web Application Security Project (OWASP) is a community working to improve the security of information systems and more specifically applications (web, mobile, APIs).

This organisation produces numerous resources, in particular guides and standards for application security, including the OWASP Top 10. It also develops open source tools such as ZAP (an interception proxy, an alternative to BURP), or Amass (to map its attack surface).

Multifactor authentication (MFA) is a central and widely used mechanism for strengthening the security of user accounts and access to a system.

Indeed, it is an authentication method that prevents many malicious attacks and exploits aimed at compromising data: brute force, session hijacking, privilege escalation, etc.

What is data pseudonymisation?

Pseudonymisation is a data protection technique, which consists of processing data in such a way that it is not possible to attribute them to a specific person without the use of additional information. More specifically, it involves replacing real personal identifiers ( last names, first names, emails, addresses, telephone numbers, etc.) with pseudonyms.

What is privilege escalation?

Privilege escalation is a key concept for attackers seeking access to sensitive information or restricted functionality on an information system. Typically, this involves exploiting security weaknesses in a given system to escalate from a limited level of access, with standard permissions, to a higher level of access, with greater rights.

On Linux, there are several techniques for escalating a user’s privileges. Exploitation of configuration weaknesses, vulnerabilities in programs and broken access control are the main ones.

What is rate limiting?

During our penetration tests on web platforms, one of the main attack vectors we use most often to discover and exploit vulnerabilities is rate limiting.

Based on this principle, we believe that any web application will, sooner or later, be confronted with a traffic-generating attack. These can take several forms, but the main ones are the following:

Server security is a major issue for companies. Indeed, being a central element in the functioning of all the components of an information system (applications, network, infrastructure, employees, etc.), servers are often the prime targets of attacks.