Network security zoning

The world is a wild place specially when we are talking about the Internet environment. There are multiple threads and multiple sources of attack. Organizations, in general, need to find the best ways to protect themselves and guarantee the continuity of their business online.

On of the best ways to build their defenses is creating different layers or zones in their infrastructures. Network security zoning mechanism allows an organization to manage a secure network environment by selecting the appropriate security levels for different zones of Internet and Intranet networks. It helps to effectively monitoring and controlling inbound and outbound traffic.

There are some different zones that we can define, the decision about which ones are going to be present in a concrete infrastructure needs to be carefully analyzed in each one of the cases. As a example, we are going to see a few of the possible zones we can implement.

  • Internet zone: Obviously, this is not a zone that we can implement, is something that it is there and we just connect. In general, we can define this zone like an uncontrolled zone that it is outside of the boundaries of our organization.
  • Internet DMZ: This is a controlled zone that provides a buffer between the internal network and the Internet.
  • Production network zone: This is a restricted zone and it has strict access controls to prevent uncontrolled traffic.
  • Intranet zone: It is a controlled zone with not heavy restriction, it is supposed to be in a controlled environment and only trusted systems and/or traffic can be  found here.
  • Management network zone: Highly restricted area or zone, with strong controls and strict policies to restrict the access of non authorized users and traffic.

As you can see, this is just a basic example list to exemplify some of the different zones we can implement in our networks.

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Network security zoning

Penetration testing phases

When we talk about penetration tests, a lot of people think that it is just a matter of start our computers, run a few tools agains the objective, do a bit of magic and, done, the pentester discovers a few vulnerabilities. But the truth is far from this point of view, maybe in the films is something like that but not in the real life.

A pentesting is a well defined process, it has its methodologies like OSSTMM, OWASP and some others. All of them, define concrete steps and procedures that a penterter should follow to perform a proper task.

One of the things that it is well defined are the different phases of a pentesting. We can find well defined phases, each one of them specifying what needs to be done and when it needs to be done. The tools you use to complete each one of these phases are not important in this article, in this article, it is just important the process.

We can find five different phases in a pentest. Each one with its boundaries, objetives and goals well defined. These five phases are:

  • Reconnaissance
  • Scanning
  • Gaining access
  • Maintaining access
  • Clearing tracks

Let see a little introduction of the different phases.

Reconnaissance

Reconnaissance refers to the preparatory phase where an attacker seeks to gather information about a target prior to launching the attack. In other words, find all the information at our fingertips. The attackers are going to use all the public sources that they can reach to find information about the target. And we are not talking just about the company, we are talking about employees, business, operations, network, system, competitors, … everything we can learn about our target. We can use web pages, social networks, social engineering, … The objetive is to know as much as we can about the victim and the elements around it.

We can find two types of reconnaissance:

  • Passive: Involves acquiring information without directly interact with the target.
  • Active: Involves interacting with the target directly by any means.

Scanning

Scanning refers to a pre-attack phase where the attacker scans the network for specific information on the basis of information gathered during the reconnaissance. In general, in this step, we are going to use port scanners, vulnerability scanners and similar tools to obtain information about the target environment like live machines, ports in each one of these machines, services running, OS details, … All this information will allow us to launch the attack.

Gaining access

Gaining access refers to the point where the attacker obtains access to a machine or application inside the target’s network. Part of this phase is when the attacker tries to escale privileges to obtain complete control of the system or, based on the access the attacker has,  it tries to compromise other systems in the network. Here we have multiple tools and different possibilities like password cracking, denial of service, buffer overflows, session hijacking, …

Maintaining access

Maintaining access refers to the phase where the attacker tries to retain the ownership of the system and make future accesses to the compromised system easier, specially in the case that  the way the attacker has used to compromise the system is fixed. The attacker can do multiple things like create users in the system, install their own applications and hide them, install backdoors, rootkits or trojans even, in some cases, the attacker can secure the compromised machine to avoid other attackers to control the machine.

Clearing tracks

Clearing tracks refers to the activities carried out by an attacker to hide malicious acts. In this phase the attacker tries to remove all the evidences about the machine being compromised trying to avoid, in first place, the detection and, in second place, obstructing the prosecution.

These are the different phases of a pentesting, and any service offered should perform all of them properly. In addition, one of the best things about performing all the phases correctly and in the adequate order is that we can use the information found in a previous phase to complete the next phase.

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Penetration testing phases

Elements of Information Security

Information security is a state of well-being of information and infrastructure in which the possibility of theft, tampering and disruption of information and services is kept low or tolerable.

The information security has the next elements:

  • Confidentiality: Assurance that the information is accessible only to those authorized to have access.
  • Integrity: The trustworthiness of data or resources in terms of preventing improper and unauthorized changes.
  • Availability: Assurance that the systems responsable for delivering, storing and processing information are accessible when required by the authorized users.
  • Authenticity: Authenticity refers to the characteristic of a communication, document or any data that ensures the quality of being genuine.
  • Non-repudiation: Guarantee that the sender of a message cannot later deny having sent the message and that the recipient cannot deny having received the message

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Elements of Information Security

Security threads

Nowadays, we have so much technology coming out that’s being consumed by consumers or being pushed out to the consumers and, one of the main problems it’s that they have no idea how they operate. They just know that it works and they have this or that cool features but they don’t imagine that each one of these new features can come with new vulnerabilities. We can discuss here about the point that the normal user don’t need to know about vulnerabilities, security or proper configuration for the new devices or features, however this should be a thought of the past. Today, everyone should have a basic knowledge about all this stuff. It´s clear that, except in a few cases, it’s going to be a big difference between the knowledge the standard user has and the knowledge an IT person has, it’s obvious, one of them it’s just using the products and the others are managing the products and, almost all the time, doing it for companies or enterprises that expect a certain level of expertise. But, it doesn’t matter who you are or what you do, the simple and undeniable truth is that everyone nowadays should have, at least, a few knowledge about the threads they have around when they are using technology because today, technology is everywhere.

This article is focused in IT persons, but I think that it can be useful for everyone that uses technology and it’s aware that they need to know or they are just curious.

There are some different issues that can be considered threads in the world of computer security and any one involved in this world should be aware of, to try to avoid or mitigate the efects. This is just a list of threads, not an explanation of how to mitigate their effects. We can divide threads in different categories:

  • Host threads: An I’m not talking just about servers that are used to deploy applications, in this category fall servers, workstations, tablets and cell phones anything that have an operative system installed and can be connected to the Internet. We can have in this category things like:
    • Footprinting: Every computer or every operative system answers in different ways to the same questions. This allows attackers to investigate and obtain information about our infrastructure.
    • Physical security: Thinks like don’t lock your laptop when you are not around, don’t lock your screen or expend a lot of time bastioning your server when it’s quite easy to have physical access to it.
    • Password threads: It shouldn’t be enough with having a password, we should have proper passwords defined in a password policy and with enough restrictions to consider them secure.
    • Malware: A thread in expansion nowadays, day after day we can see more cases of malware, we should have control about what is installed in our host and what the host is executing. We shouldn’t install things just using the “Next” button without read the different screens in the wizards, this is how you end up with new bars in your browser or applications that you don’t know what they are.
    • Denial of Service: It does’t matter if it’s intentional or non-intentional, the result is that your system is not going to be available, you can lose money, customers, reputation, …
    • Unauthorized access: No one that it’s not allowed to use a system should be allowed to log into the system, period.
    • Privilege escalation: It’s closely related with the previous one, if I can access illegitimately the system I can try to obtain more privileges in it. Creating accounts with more privileges for example.
    • Backdoors: One of the things that attackers are going to do after gain access to our systems, it’s to create a backdoor to be able to return later and access the system again in a easier way. One very common way to do that is creating service accounts. For this reason this is one of the things that we should revise.
  • Natural and physical threads:
    • Natural disasters: Earthquakes, hurricanes, floods or any other natural disaster. It’s obvious that try to prevent this kind of events it’s out of discussion but we should have the proper plans, procedures or policies to try to mitigate their effects.
    • Physical threads: Like thefts, dropping the laptop or the cell phone, anything that can affect directly to the physical device. We need to be prepared to mitigate the loss of information.
    • Power: Power problems can affect our devices or components, can destroy or affect data  or stress our devices.
    • End of life: Every device has life and in some point it needs to be retired. Maybe because is not powerful enough to match your business requirements or just because it’s too old. But any of our devices, in general, it’s going to have a HD that it has been storing  our information in some point and we should take care of this. And, I’m not talking just about laptops or PCs, I’m including printers or any other device that has a HD. The wrong treatment of these devices can derivate in a leak of information.
  • Application threads:
    • Configuration threads: Misconfigurations or default configurations can be a great threat for our devices and our organizations. We should pay attention to everything that we are configuring, it does’t matter if it’s hardware or software. We should read the manuals properly and even, if it’s necessary, look for some training.
    • Buffer overflows: This is an application trying to store more information in the buffer than what intended to hold. This usually is caused by errors during the development. Any in-house development should be reviewed carefully, any open source code should be reviewed carefully and all the scripts or codes our developers or IT persons copy and paste from the Internet should be reviewed.
    • Data and Input Validation: All the information coming into our application needs to be previously validated to avoid injection. Code injection, SQL injection, any injection.
  • Human threads: With this point we can write a book, and probably a few of them. The biggest and one of the more dangerous threads is us. We are humans and we are falible. Exists a hacking discipline focus in this kind of thread: Social engineering. How to obtain from people what you need. We need to train our people, we need to have policies and mitigation measures and we need to be prevented, there is no other way.
  • Network threads:
    • Sniffing and Eavesdropping: Anyone can be sniffing in your network trying to obtain information to perform and attack.
    • ARP Spoffing: Trying to simulate the attacker computer is the default gateway or any other interesting computer in your network.
    • Denial of Service: Yes, here we have this thread again.

This is just a list of some general threads we can find around us all the time and something about we need to take care when we are auditing our systems or trying to penetrate them. I hope it´s useful, at least, to have them in the same place to review it.

See you.

Security threads