What Is a Secure Web Gateway (SWG)?

A secure web gateway (SWG) is an on-premises or cloud-delivered network security technology that filters internet traffic and enforces corporate and regulatory policy compliance.

How Does an SWG Work?

The secure web gateway sits between users and the internet to filter traffic and enforce acceptable use and security policies.

Primary SWG capabilities include:

• URL filtering
• Antimalware and threat prevention
• Application control capabilities

The role of an SWG revolves around managing and regulating data flow between the network and the internet.

SWG deployment can take various forms, including:

• Physical servers
• Cloud-based virtual machines and services
• Software applications

Secure web gateways work by inspecting traffic from client devices aiming to connect with internet resources. Each outgoing web request from a client device first connects through the SWG. Serving as the gateway, the SWG authenticates the user and examines the request, ensuring it doesn’t violate acceptable use policies. The SWG only allows the request to proceed if it’s determined to be appropriate and safe. Incoming data undergoes a similar inspection before it can reach users.

SWGs essentially shield users from online threats while enforcing acceptable use policies. They serve as data checkpoints by safeguarding internet access, blocking malicious web traffic and malware, and protecting organizations from data leaks.

Why Are SWGs Important?

Secure web gateways are important because they safeguard organizations against concealed cyberthreats, especially within encrypted web traffic, while also mitigating the risk of operational and business disruption.

A secure web gateway is a crucial element in today's digital landscape due to the escalating complexity and frequency of cyberthreats. Cybercriminals continually devise new tactics and techniques to breach security defenses, one of which includes camouflaging malicious code in seemingly legitimate websites. As users access these compromised websites, they inadvertently leak credentials or expose organizations to harmful code, which can wreak havoc if left unnoticed.

In such a risk-laden environment, the absence of a robust security gateway significantly amplifies the risk to an organization's digital assets. Such risk could lead to unauthorized access, data theft and disruption of business operations, especially with the increasing prevalence of widespread phishing and ransomware attacks. Without the security barrier provided by an SWG, a ransomware attack could effectively hold an organization hostage, leading to financial and reputational harm.

The use of encrypted traffic is now commonplace, with HTTPS constituting the majority of web traffic. An organization is at risk of security threats concealed within encrypted channels if it lacks an SWG that can effectively decrypt and inspect this traffic.

Benefits of SWGs

• Reduces the external attack surface by minimizing potential attack vectors exploited by threat actors
• Supports businesses in digital, cloud and workforce transformations
• Provides remote workers secure access to the internet, SaaS applications and necessary online resources
• Safeguards internet connectivity critical for IT operations, including servers and headless devices
• Strengthens cybersecurity infrastructure by protecting critical data and operations connected to the web

SWG Features

URL Filtering

URL filtering controls access to websites, preventing access to inappropriate or malicious web content. Web traffic is categorized as either permitted, denied, malicious or unknown/suspicious based on the URL category, users, groups or devices. The web traffic is then assigned a low, medium or high risk level. This allows administrators to properly secure its networks against web-based threats, such as phishing, malware, ransomware and command-and-control (C2) connections and also provides insight into who is accessing risky websites.

Threat Prevention

Threat prevention stops injection attacks, exploits and malicious C2 that target software and web application vulnerabilities with an intrusion prevention system. Advanced threat prevention capabilities can detect anomalous packet and traffic patterns and prevent web attacks using hacking tools.

Application Control

This functionality gives administrators the ability to create granular web access controls based on user identification, limiting or blocking usage of web applications, app functionality and widgets, thus ensuring data privacy and security within an organization.

Data Loss Prevention (DLP)

DLP ensures that critical or sensitive information doesn’t escape an organization's network. It safeguards businesses from unintentional loss of valuable data by monitoring data movement and by adhering to industry compliance regulations and standards.

Antivirus and Antimalware

Antivirus software is designed to prevent, detect and eliminate harmful software, such as viruses, Trojans, worms, spyware and adware. It employs real-time virus signatures to protect end-user devices from infection.

Antimalware scans and blocks malicious files from web content. These solutions use network sandboxing techniques to analyze for malware and mitigate risks from unknown executables and fileless attacks.

DNS Security

Adversaries exploit DNS to establish reliable C2, attack hosts inside the corporate network from the internet, perform distributed denial-of-service (DDoS) attacks, and even cause reputational harm by taking over domains. DNS security tools identify and disrupt these types of attacks.

HTTPS Inspection

HTTPS inspection scrutinizes and secures SSL-encrypted traffic passing through the gateway. It decrypts the traffic with the sender's public key, inspects and safeguards it, then re-encrypts the content to send back to the sender.

Common SWG Deployment Challenges

Complexity in Functionality

A common SWG deployment challenge is in its inherent complexity. If implemented separately, an SWG can become another point product in a disjointed security stack that requires ad hoc management.

However, if natively integrated with adjacent security technologies, for example, within a secure access service edge (SASE) framework, security teams can have improved visibility and single-pane-of-glass management for easier monitoring and security enforcement.

Impact on User Experience

The process of securing internet traffic using traditional on-premises infrastructure can negatively affect user experiences. Backhauling all web traffic to a centralized data center will likely cause latency and performance degradation, leading to poor user experiences. Poor user experience can hinder worker productivity, cause frustration and lead users to disable or circumvent security controls.

Evolution of Cyberthreats

The continuous advancement of cyberthreats is another significant challenge. Modern cyberattacks have evolved to include tactics where adversaries use legitimate SaaS platforms to host malicious content, employ phishing kits to scale attacks and execute meddler-in-the-middle attacks to steal credentials. As cybercriminals innovate their attack strategies, traditional SWG solutions that rely on hashes, static signatures and offline crawling of web content become less effective.

How Do SWGs Enforce Acceptable Use Policies?

A secure web gateway can authenticate users through methods like single sign-on or explicit usernames and passwords. Based on this identity, the SWG can then enforce user-specific access rules. For example, if a user attempts to access a hacking website, the SWG would identify this user and apply the appropriate level of access. It may block a regular user but permit access to someone from the cybersecurity team who needs to conduct research on such websites.

Companies often implement acceptable use policies that define permitted online activities. These policies can block access to certain categories of websites, such as gambling or adult content.

How Do SWGs Secure Remote Workers and Branch Offices?

Cloud-delivered SWGs are particularly useful for securing remote workers because they serve as an intermediary between globally distributed users and the internet. Branch offices without a data center or on-premises SWG can also benefit from a cloud-delivered model rather than backhauling its web traffic to a distant data center.

For many years, however, SWGs were deployed as on-premises web proxy appliances, even for branch and remote user traffic, with traffic sent through dedicated IPsec tunnels or virtual private networks (VPNs). However, these precloud SWGs, built on a hub-and-spoke architecture, were never designed to support today’s distributed networks.

What Role Do SWGs Play in Compliance with Regulatory Requirements?

Secure web gateways serve a vital function in achieving regulatory compliance across diverse industry sectors. SWGs are especially useful for sectors like healthcare or financial services that handle especially sensitive data and face strict auditing requirements. Utilizing a proxy, as well as DLP capabilities, facilitates traffic inspection for potential data leakage or the unauthorized sharing of sensitive customer information, thereby upholding regulatory standards.

With regard to regulations like the General Data Protection Regulation (GDPR) in Europe, SWG and DLP provide the necessary controls to safeguard the data of EU residents. They maintain data processing and transfer inline with regional regulations, mitigating potential infringements of data residency rules.

Moreover, logs and reports are useful during audits, offering detailed records of data transfers, accessed websites and possible security incidents to demonstrate regulatory compliance. Additionally, granular control over application access offered by SWGs can be indispensable in sectors that have stringent regulations around specific SaaS applications.

Customizability provides a further compliance advantage. SWGs can be tailored to meet specific industry or geo-specific regulations, enabling businesses to uphold stricter rules for data access, storage or transfer.

Lastly, regularly updated SWGs aid organizations in staying compliant with new or changing regulations. As regulatory landscapes evolve, appropriate updates can ensure that businesses can promptly adjust their compliance strategies.

SWGs vs. Firewalls

While firewalls focus on network layer inspections, SWGs provide an in-depth look at the application layer. Although SWGs deliver advanced functionality, they are not intended to replace firewalls, but to supplement the security mechanisms firewalls provide.

Firewalls and SWGs serve distinct, yet complementary roles in network security. First-generation firewalls, functioning at network Layers 3 and 4, concentrate on inspecting IP addresses, ports and router-based protocols. This inspection determines the permissibility of connections based on specific network parameters.

Next-generation firewalls expanded this scope, operating at both the network layer (Layers 3 & 4) and the application layer (Layer 7). These firewalls inspect packets deeper within the OSI model, applying security measures based on various types of traffic or specific applications. The functionality covers both rudimentary network aspects and more sophisticated application data.

Conversely, traditional SWGs primarily work at the application layer (Layer 7). They provide a security inspection that scrutinizes applications, web traffic and a broader array of ports and protocols that extend beyond traditional networking bounds. Modern cloud-delivered SWGs, as part of a security service edge (SSE) platform, combine SWG functionality, including advanced URL filtering, SSL decryption, SaaS application control and advanced threat prevention with firewall capabilities for a more holistic web security defense.

SWGs vs. Proxies

When SWGs were first defined as a category in the security market, most solutions were provided by web proxy vendors. However, SWGs and web proxies are not the same thing. A proxy is a networking function, whereas SWG is a security solution.

A proxy is a dedicated computer or software that sits between an end client (such as a desktop computer or mobile device) and a desired destination (such as a website, server or web- or cloud-based application). By acting as an intermediary between the client and destination, proxies can inspect traffic and shield the client’s Internet Protocol (IP) address from the destination, providing a layer of security and privacy.

There are two primary types of proxies: explicit and transparent. An explicit proxy requires client-side configuration, so users are usually aware of its presence due to device configuration and authentication. On the other hand, a transparent proxy is invisible to users and redirects client requests without requiring any client-side configuration. Both types serve specific purposes and offer different benefits and drawbacks in the realm of cybersecurity.

The Evolution of SWGs

Secure web gateways have been in existence since the late 1990s to early 2000s. The need for SWGs grew with the rise of the internet and the subsequent increase in web-based threats. As businesses and individuals began to rely more heavily on the internet, the need for solutions to screen and filter malicious web content became apparent.

The functionalities traditionally provided by secure web gateways were eventually integrated into a concept known as security service edge (SSE). SSE was developed to enhance public application access by integrating internet security through a secure web gateway. In addition to SWG, SSE also facilitates safe access to private applications, traditionally accessed via VPN tunnels, by incorporating more pervasive and secure connections via Zero Trust Network Access (ZTNA).

Then SSE began absorbing cloud access security brokers (CASB) and data loss prevention (DLP) capabilities, along with firewall as a service (FWaaS), to form a comprehensive set of security capabilities.

Finally, networking solutions like software-defined wide area networks (SD-WAN) were incorporated. The combination of SSE and SD-WAN gave rise to a new framework known as secure access service edge (SASE).

SASE represents the current stage of evolution for secure web gateways. This indicates a trend toward more comprehensive and integrated approaches to cybersecurity and network management with a single platform.

The Future of SWGs

The future of SWGs is shifting toward cloud-delivered models enhanced with AI, emphasizing scalability and cyber resilience for the next decade.

The foundational SWGs were built on top of on-premises web proxy appliances located in campuses/headquarters or data centers. This model was suitable when employees primarily worked from centralized office locations. However, with the onset of remote work and the adoption of cloud-based SaaS applications, routing all web traffic through on-premises appliances became less efficient.

Over time, many SWG vendors have transitioned from on-premises web proxies to cloud-delivered proxies. Cloud-delivered SWG proxies can be helpful for organizations with well-established proxy architectures or for compliance requirements. Conversely, many enterprise organizations without proxy requirements have also adopted modern SSE solutions without utilizing its proxy capabilities.

Artificial intelligence (AI) has also had a significant impact on recent SWG developments. AI aids with threat detection and security operations by identifying and stopping web attacks inline and in real time. These threats range from spear phishing to multivector intrusions. AI-driven SWGs can swiftly analyze large-scale web traffic and counter dynamic and highly evasive web threats more effectively.

For future planning, organizations need to consider more than simply updating existing SWG deployments. It is essential that they also address operational needs, including native integration, simplified management and digital experience monitoring with AIOps, for the next three-to-five years. The right solution will offer dynamic capacity, elastic scalability, high availability and uncompromised cyber resilience. The primary objective is to ensure secure access to the internet and SaaS apps, all while improving operations and navigating evolving web threats.

How to Choose a Secure Web Gateway

When an organization is in the process of selecting a secure web gateway, several critical factors come into play.

First, choosing an SWG isn't solely about security. Equally significant is the balance between protective measures and seamless user connectivity. Efficient, uninterrupted access to resources for users is a key consideration.

Operational complexity can also increase security risks, so simplifying management by reducing the number of user interfaces, products, dashboards and vendors is crucial. Organizations should view the SWG as a foundational step toward a unified and comprehensive SSE/SASE platform. A consolidated solution offers the advantage of centralized policy management, enabling IT security teams to oversee operations through a streamlined process.

An approach worth considering involves selecting a vendor that furnishes a single SASE solution. Such a solution envelops an array of services, including FWaaS, CASB, SWG, Zero Trust Network Access (ZTNA), and SD-WAN, under the umbrella of a single unified security platform.

Opting for a single vendor for this broad suite of services eliminates navigating multiple interfaces or learning to operate a multitude of products. Streamlining can enhance operational efficiency for organizations contemplating SWG implementation, among other security services.

Additional components that may be useful when choosing an SWG could include:

• Future scalability and adaptability to evolving threats.
• The vendor's track record and reputation.
• Level of customer support provided.

Secure Web Gateway FAQs