Introduction to Public Key Certificate

A digital certificate is a data file that allow, on the one hand, the non-repudiation and the integrity of data, and on the other hand, to identify and to authenticate a person or an organization and also to encode communications.

A digital certificate includes several information, as:

• A public key
• Authentication information
• A validity time
• An issuer that signs the certificate

This last point is crucial to verify the trustworthiness of a certificate. For this, when a certificate is received, a chain of trust is built to a certificate authority.

To explain the working of the chain of trust, let’s present some notions:

The Metasploit framework is an open source tool, allowing searching, analysing and exploiting vulnerabilities. It has many modules and tools that can be very useful during intrusion tests, whether on Web applications or on a company’s information system.
Although often used relatively basically, for example to launch a simple exploitation module on a target, this framework has options and tools that make it a key ally for a pentest. We will therefore see here how to use the Metasploit framework in an optimized way.

In this previous article, we have seen what a SSRF vulnerability is, and how, in general, it can be exploited. We had placed ourselves in a quite simple theoretical framework, but various elements (either due to the vulnerability itself or due to security implementations) can make the task more complicated.

In this article, we will have a look at various methods to go further. On
the agenda:

• Various methods for manually bypassing filters;
• SSRFMap: a semi-automatic operating tool.

Now that we have introduced four main functionalities of Burp Suite in the previous article, we will go a bit further with some functionalities and extensions that can increase the quality of an audit and your efficacy.

Functionalities and screenshots presented in this article are from the version Professional 2.1.01.

Alternative to classic Bluetooth, Bluetooth Low Energy is chosen increasingly for the IoT. This technology, also known as the abbreviation BLE, is establishing itself for connected devices, as it is ideal to send small amounts of data between devices and to preserve the battery; which matches the IoT’s needs perfectly. Classic Bluetooth, on its side, is used to send large amounts of data between a device and a user (wireless headphones and speakers are using Bluetooth for example).

USB devices are so convenient. Whenever we need to store small amounts of data, we use a USB stick. Everyone owns one and we generally trust it to be safe. USB keys are one of the main ways to do industrial espionage, but attacks against random civilians and companies are also common.

The 2018 Honeywell report on USB threat to industrial operators analyzed a sample of 50 locations. Energy, chemical manufacturing, pulp & paper, oil & gas and other industrial facilities were concerned by the study. Among the locations targeted, 44% blocked a suspicious file originating from USB ports and 15% of the threats detected and blocked were high-profile threats, like Stuxnet, Wannacry and Mirai.

Internet of Things security is a current topic, however penetration testing on connected devices are far from being a widespread practice. Most manufacturers prioritize product functionalities and design first. However, even with a “security by design” approach, pentesting remains essential to know the real security risks, and then to take the necessary measures.

What is a Cross Site Request Forgery Attack?

The CSRF is an attack that forces an end user to perform unwanted actions and without noticing on a web application he/she is currently authenticated.
CSRF attacks specifically target requests that make modifications, not data theft, because the attacker has no way of seeing the response of the falsified request. The outcome of the actions is what interests the attacker.

This type of attack is based on the fact that when a user is authenticated on an application, it will usually provide a session ID that its browser stores in a cookie.

Each time the user sends a request to the server, the browser will also automatically send this session cookie. You can find in linked article more information about CSRF attacks.

Keep in mind that a CSRF attack only needs that the user stays connected (without having an open page or tab of the website) to be working.

We often think that a firewall restrictive enough protects the access to non-open services. We also believe that only a compromise machine can give access to the internal network. We are indeed wrong, and that’s what we are going to see with a web application vulnerability: The Server-Side Request Forgery, or SSRF.

What is an SSRF?

From a vulnerable web application, an SSRF makes possible to interact with the server, in order to extract files and to find its other active services. But there is more. It is also possible to scan the internal network to cartography IP and open ports.

During our audits, we often encounter user enumerations that could be easily avoided with the right methods. In this article, we will discuss user enumerations on login forms, password reset forms, and account creation forms. However, user enumerations may be present on other features, such as search forms or message submissions.