O que é Firewall?

History of Firewalls

firewall existem desde o final da década de 1980 e começaram como filtros de pacotes, que foram configurados novamente para examinar pacotes, ou bytes, transferidos entre computadores. Embora firewall de filtragem de pacotes ainda estejam em uso hoje, firewall percorreram um longo caminho à medida que a tecnologia se desenvolveu ao longo das décadas.

• Vírus Geração 1
  • Geração 1, final da década de 1980, os ataques de vírus em PCs independentes afetaram todas as empresas e impulsionaram produtos antivírus.
• Rede Geração 2
  • Geração 2, meados da década de 1990, os ataques da Internet afetaram todos os negócios e impulsionaram a criação do firewall.
• Aplicativo Geração 3
  • Geração 3, início dos anos 2000, explorando a vulnerabilidade no aplicativo que afetou a maioria das empresas e impulsionou os produtos do Sistema de prevenção de intrusão (Intrusion Prevention System, IPS).
• Carga útil da geração 4
  • Geração 4, Aprox. 2010, aumento de ataques direcionados, desconhecidos, evasivos e polimórficos que afetaram a maioria das empresas e impulsionaram produtos anti-bot e sandboxing.
• Geração 5 Mega
  • Geração 5, Aprox. 2017, megaataques multivetoriais e em grande escala usando ferramentas de ataque avançadas e estão impulsionando soluções avançadas de prevenção de ameaças.

Em 1993, o CEO da Check Point, Gil Shwed, introduziu o primeiro firewall de inspeção com estado, o FireWall-1. Vinte e sete anos depois, um firewall ainda é a primeira linha de defesa de uma organização contra o ciberataque. firewall atual, incluindo o Firewall de próxima geração e firewallde rede, suporta uma ampla variedade de funções e capacidades com recursos integrados, incluindo:

• Prevenção contra ameaças de rede
• aplicativo e controle baseado em identidade
• Suporte à nuvem híbrida
• Desempenho escalável

The Firewalls Evolution

Just like the networks they protect, firewalls have undergone a significant amount of change over the last decade. Even the earliest firewall tooling was essential to network security, as their 1980s counterparts first came into existence as packet filtering tools.

Early Development: Packet-Filtering Firewalls

The first generation of firewalls, introduced in the late 1980s, employed simple packet filtering. These tools examined data packets at the network layer (OSI Layer 3), and filtered the packets that a network responds to through parameters such as IP addresses, ports, and protocols. However, their lack of contextual awareness and overwhelming focus on individual packets made them vulnerable to complex attacks like IP fragmentation.

The Emergence of Stateful Inspection

The 1990s saw the advent of stateful inspection firewalls, pioneered by Check Point. These second-generation firewalls continuously monitored the state of connections, ensuring that packets were part of an established session. This enhancement significantly bolstered security.

Application Layer and Proxy Firewalls

Application layer firewalls and proxy firewalls emerged around the same time. The former operated at Layer 7, able to analyze and apply application-specific data and rulesets. They were also highly secure – boasting the ability to completely separate traffic requests from the underlying network architecture – but early models suffered from limited processing power and bad latency.

Unified Threat Management (UTM) and Next-Generation Firewalls (NGFW)

The 2010s saw the advent of UTM systems, which sought to combine a firewall’s reactivity with the extra data points from antivirus, intrusion detection, and other enterprise security systems. NGFWs were able to push these integration capabilities by adding deep packet inspection, advanced threat protection, and application-level filtering.

Modern Adaptations: Cloud and AI

Today, firewalls have adapted to cloud environments and containerized applications, giving rise to Firewall-as-a-Service (FWaaS). Building upon the foundation of cross-environment data, AI and machine learning are increasingly being deployed for their superior anomaly detection, predictive threat analysis, and adaptive policy enforcement.

From static filters to intelligent, context-aware systems, firewalls have continuously evolved to meet the demands of an ever-changing threat landscape. Let’s delve into all the features that make today’s firewalls so critical.

Os diferentes tipos de firewalls

Filtragem de pacotes

Packet filtering is a network security technique used in firewalls to control data flow between networks. It evaluates the headers of incoming and outgoing traffic against a set of predefined rules, and then decides whether to allow or block them.

Firewall rules are precise directives that form a critical part of firewall configurations. They define the conditions under which traffic is permitted or blocked based on parameters such as source and destination IP addresses, ports, and communication protocols. In enterprise environments, these individual rules are nested together to form Access Control Lists (ACLs). When processing traffic, the firewall evaluates each packet against the ACL rules in sequential order. Once a packet matches a rule, the firewall enforces the corresponding action—such as allowing, denying, or rejecting the traffic—without further evaluation of subsequent rules. This structured and methodical approach ensures that network access is tightly controlled and consistent.

Serviço de proxy

Since firewalls are happy to sit at the edge of a network, a proxy firewall is naturally well-suited to acting as a single point of entry: in doing so, they’re able to assess the validity of each connection. Proxy-service firewalls completely separate the internal and external, by terminating the client connection at the firewall, analyzing the request, and then establishing a new connection with the internal server.

Stateful Inspection

Stateful packet inspection analyzes the contents of a data packet and compares them to information about packets that have already traversed the firewall.

Stateless inspection analyzes each packet in isolation: stateful inspection, on the other hand, pulls in previous device and connection data to further understand network traffic requests. This is more akin to viewing network data as a continuous stream. By maintaining a list of active connections, and evaluating each from a more macroscopic perspective, stateful firewalls are able to assign network behavior to long-term user and device profiles.

Firewall de aplicativo da web (Web Application Firewall, WAF)

A Web Application Firewall (WAF) wraps around a specific application and examines the HTTP requests being sent to it. Similar to other types of firewall, it then applies predefined rules to detect and block malicious traffic. The components being scrutinized include headers, query strings, and the body of HTTP requests  – all of which contribute to signs of malicious activity. When a threat is identified, the WAF blocks the suspicious request and notifies the security team.

AI-Powered Firewall

Firewalls are essentially powerful analytical engines: they’re perfectly suited for the implementation of machine learning algorithms. Because ML algorithms are able to ingest and analyze far greater amounts of data far faster than their manual counterparts, AI-powered firewalls have consistently been able to outperform their older counterparts when handling novel (zero day) threats.

One of the more common implementations of AI within firewalls, for instance, is User and Endpoint Behavioural Analysis (UEBA). This ingests the historical data from entire networks, and establishes how every user and endpoint typically interacts with it – what resources they use, when they access them, etc.

High Availability Firewalls and Hyperscale, Resilient Load-Sharing Clusters

A high availability (HA) firewall is designed to maintain network protection even in the event of firewall failure. This is achieved via redundancy, in the form of HA clustering: multiple firewall peers working together to deliver uninterrupted protection. In the event of device failure, the system automatically transitions to a peer device, therefore maintaining seamless network security. Above and beyond traditional ‘high availability’ designs,  many organizations now need hyper scalable and telco-class resilient firewall systems to assure 99.99999%+ uptime and up to 1,000 Gbps of network throughput with full threat prevention.  An intelligent load-sharing firewall design distributes network traffic across a firewall cluster. It can also automatically reallocate additional firewall resources to critical applications during unexpected peak traffic conditions or other predefined triggers, and then reassign those firewall resources back to their original group after conditions are back to normal. This optimizes performance and prevents any single device from becoming overwhelmed, and assures maximum network performance under all conditions.

Virtual Firewall

Firewalls were traditionally hardware-exclusive, as they needed the heavy CPU power to manually flick through every rule in the ACL. Now, however, that processing power can essentially be outsourced thanks to firewall virtualization. Virtual systems support internal segmentation: where one tool can be used to set up and monitor multiple segmented firewalls, allowing sub-firewalls to have their own security policies and configurations.

Virtual firewalls offer many advantages: multi-tenancy environments, for instance, benefit from this segmentation. It also allows for larger organizations to implement network segmentation in a more streamlined way, through one central tool. Other than that, virtual firewalls can offer all the same capabilities as their hardware-based counterparts.

firewallem nuvem

It’s common to see people conflate virtualized firewalls with cloud firewalls, but there is a distinction: whereas virtual describes the underlying architecture, cloud firewalls refer to the enterprise assets they are protecting. Cloud firewalls are those used to protect organizations’  public and private cloud-based networks.

Firewall como serviço (Firewall as a Service, FWaaS)

Since cloud virtualization now allows for processing power to be purchased and used remotely, virtual firewalls are now possible. This opens up new possibilities for firewall architecture – one of which is Firewall as a Service (FWaaS).

FWaaS, like any SaaS, is a pre-built firewall solution that is deployed through the cloud. Instead of all enterprise traffic being routed and analyzed via an in-house server room, FWaaS’ unique offering is often its global Points of Presence, which allows for more local (and latency-free) firewall deployment.

Gerenciado firewall

Finally, it’s all well and good having a firewall – but as we’ll cover shortly, this tool needs continuous refinement and tweaking. Some enterprises find that the human demands of this can quickly overwhelm a lean cybersecurity team. So, many choose to route their traffic via a managed firewall – which is continuously monitored for threats, anomalies, or unusual traffic patterns. These outsourced firewalls can also benefit from the provider’s advanced tooling and threat intelligence.

The Importance of Firewall Protocols

Even basic firewalls are able to dig into the source, destination, and protocols that every packet is conforming to. But visibility alone doesn’t prevent attacks; firewall rules govern how the firewall tool reacts to each packet – ultimately either allowing it through to the enterprise network, or denying it.

These rules are fundamental to maintaining network security by controlling access to and from systems, ensuring that only authorized traffic passes through while malicious or unwanted data is blocked. To save time, most off-the-shelf firewalls offer preconfigured rulesets. After all, many threats are universal, regardless of the specifics of your industry or employees – especially when attackers are able to scan any public-facing networks for common vulnerabilities. By shipping with preconfigured rulesets, modern firewalls allow for an immediate reduction in potential threats that could hit your enterprise; a boon to deployment, allowing administrators to cut a lot of manual setup that a new tool typically demands. This reduces errors and ensures adherence to industry best practices.

Por que precisamos firewall?

Firewalls, especially Next Generation Firewalls, focus on blocking malware and application-layer attacks. Along with an integrated intrusion prevention system (IPS), these Next Generation Firewalls are able to react quickly and seamlessly to detect and combat attacks across the whole network. Firewalls can act on previously set policies to better protect your network and can carry out quick assessments to detect invasive or suspicious activity, such as malware, and shut it down. By leveraging a firewall for your security infrastructure, you’re setting up your network with specific policies to allow or block incoming and outgoing traffic.

Firewall Security Best Practices

Firewalls aren’t a set-it-and-forget-it solution. The attacks facing your organization are in constant flux, and firewalls that rely solely on manual rule updates demand just as much time and attention.

Set Up Rules According to Least Privilege Principles

Foundational to effective firewall rule management is the principle of least privilege. It functionally means only traffic that serves a specific, necessary business function is allowed. By adhering to this principle, it’s all but guaranteed that future rule changes minimize risk, maintain greater control over network traffic, and limit unnecessary cross-network communication. Applying this to rules demands that details such as source and destination IP addresses (or ranges) and destination ports are always defined. This is why overly permissive rules like “Any/Any,” need to be replaced with an explicit deny/allow strategy for all inbound and outbound activity.

Maintain Up To Date Documentation

As pre-configured rules are changed and updated, clear and comprehensive documentation is essential. Anyone on the network security team should easily understand the purpose of each rule from the documentation. At a minimum, you should record details such as the purpose of the rule, the services it affects, the users and devices involved, the date it was implemented, the rule’s expiration date if temporary, and the name of the analyst who created it.

Protect the Firewall Itself

The firewall isn’t just a critical piece of enterprise safety: it’s the most public-facing piece of any network infrastructure, making unmanaged firewalls themselves a threat. To secure the firewall, a few key best practices are mandatory: insecure protocols like telnet and SNMP should be disabled entirely; configurations and log databases should be backed up; and a stealth rule should be implemented to protect the firewall from network scans. Finally, keep a regular eye on the updates available for the firewall solution.

Group Rules – and Networks – into Corresponding Categories

Segmenting enterprise networks into corresponding security levels is another foundational best practice for network security, and firewall rules are perfectly well-suited for enforcing these segments. To streamline management, organize rules into categories or sections based on their function or related characteristics. This approach allows you to structure the rules in the most effective order and ensures better oversight.

AI-powered firewalls are increasingly able to automate the rules and documentation they’re based on: these massive strides in efficiency are the main reason why NGFWs are replacing their older models.

Inspeção da camada de rede versus camada de aplicativo

A camada de rede ou os filtros de pacotes inspecionam os pacotes em um nível relativamente baixo da pilha de protocolos TCP/IP, não permitindo que os pacotes passem pelo firewall, a menos que correspondam ao conjunto de regras estabelecido, onde a origem e o destino do conjunto de regras são baseados no protocolo da Internet ( endereços IP) e portas. firewall que faz a inspeção da camada de rede tem melhor desempenho do que dispositivos semelhantes que fazem a inspeção da camada de aplicativo. A desvantagem é que aplicativos ou malware indesejados podem passar pelas portas permitidas, por exemplo tráfego de saída da Internet através dos protocolos web HTTP e HTTPS, portas 80 e 443, respectivamente.

A importância do NAT e VPN

firewall também executa funções básicas de nível de rede, como Tradução de Endereço de Rede (NAT) e Rede Privada Virtual (VPN). A rede Address Translation oculta ou traduz endereços IP internos de clientes ou servidores que podem estar em um “intervalo de endereços privados”, conforme definido na RFC 1918 para um endereço IP público. Ocultar os endereços do dispositivo protegido preserva o número limitado de endereços IPv4 e é uma defesa contra o reconhecimento da rede, uma vez que o endereço IP fica oculto da Internet.

Da mesma forma, uma rede privada virtual (VPN) estende uma rede privada através de uma rede pública dentro de um túnel que geralmente é criptografado onde o conteúdo dos pacotes é protegido enquanto atravessa a Internet. Isso permite que os usuários enviem e recebam dados com segurança em redes públicas ou compartilhadas.

Firewall da próxima geração e além

O Firewall da próxima geração inspeciona pacotes no nível do aplicativo da pilha TCP/IP e é capaz de identificar aplicativos como Skype ou Facebook e impor políticas de segurança com base no tipo de aplicativo.

Hoje, o dispositivo UTM (Unified Threat Management) e o Firewall de próxima geração também incluem tecnologias de prevenção de ameaças, como Sistema de prevenção de intrusão (Intrusion Prevention System, IPS) (IPS) ou Antivírus para detectar e prevenir malware e ameaças. Esses dispositivos também podem incluir tecnologias de sandbox para detectar ameaças em arquivos.

À medida que o cenário da segurança cibernética segue evoluindo e os ataques se tornam mais sofisticados, os Firewalls de Próxima Geração continuarão a ser um componente essencial da solução de segurança de qualquer organização, quer você esteja no data center, na rede ou na nuvem.

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Combining cutting-edge threat prevention, unparalleled performance, and streamlined efficiency, Check Point Quantum’s advanced capabilities include intelligent traffic inspection, seamless integration with cloud services, and in-depth incident automation. See for yourself how Quantum boasts effortless scalability and centralized policy management with a demo.

To learn more about the essential capabilities your Next Generation Firewall needs to have, download the Next Generation Firewall (NGFW) Buyer’s Guide today.