What is 802.1x? How Does it Work?

What is 802.1x? How Does it Work?

802.1x can be a complex topic to digest and, like the rest of networking, it can be overwhelming where to start learning about it. Luckily, we’ve been fortunate enough to have worked with 802.1x since it’s inception, and did the best job we could to explain everything we know about it. Below we will cover how 802.1x works, it’s components, what it’s used for, vulnerabilities, how to set it up, and much much more.

What is IEEE 802.1x?

Devices attempting to connect to a LAN or WLAN require an authentication mechanism. IEEE 802.1x, an IEEE Standard for Port-Based Network Access Control (PNAC), provides protected authentication for secure network access.

An 802.1x network is different from home networks in one major way; it has an authentication server called a RADIUS Server. It checks a user’s credentials to see if they are an active member of the organization and, depending on the network policies, grants users varying levels of access to the network. This allows unique credentials or certificates to be used per user, eliminating the reliance on a single network password that can be easily stolen.

How does 802.1x work?

802.1x is a network authentication protocol that opens ports for network access when an organization authenticates a user’s identity and authorizes them for access to the network. The user’s identity is determined based on their credentials or certificate, which is confirmed by the RADIUS server. The RADIUS server is able to do this by communicating with the organization’s directory, typically over the LDAP or SAML protocol.

What is 802.1x EAP Security?

The standard authentication protocol used on encrypted networks is Extensible Authentication Protocol (EAP), which provides a secure method to send identifying information over-the-air for network authentication. 802.1x is the standard that is used for passing EAP over wired and wireless Local Area Networks (LAN). It provides an encrypted EAP tunnel that prevents outside users from intercepting information.

The EAP protocol can be configured for credential (EAP-TTLS/PAP and PEAP-MSCHAPv2) and digital certificate (EAP-TLS) authentication and is a highly secure method for protecting the authentication process.

WPA2-Enterprise Protocols

Level of Encryption Authentication Speed Directory Support User Experience
EAP-TLS Public-Private Key Cryptography Fast – 12 Steps SAML/LDAP/MFA Servers Best
PEAP-MSCHAPV2 Encrypted Credentials Slow – 22 Steps Active Directory Acceptable
EAP-TTLS/PAP Non-Encrypted Credentials Slowest – 25 Steps Non-AD LDAP Servers Poor

What is 802.1x used for?

802.1x is used for secure network authentication. If you are an organization dealing with valuable and sensitive information, you need a secure method of transporting data. 802.1x is used so devices can communicate securely with access points (enterprise-grade routers). It was historically only used by large organizations like enterprises, universities, and hospitals, but is rapidly becoming adopted by smaller businesses because of the growing threats in cyber security.

802.1x is often referred to as WPA2-Enterprise. In contrast, the Pre-Shared Key network security most often used at home is referred to as WPA2-Personal. WPA2-Personal is not sufficient for any organization dealing with sensitive information and can put organizations at serious risk for cyber crimes.

Are IEEE 802.1x and Wi-Fi the same?

Almost. The IEEE 802.1x standard was first designed for use in wired Ethernet networks. Wi-Fi is a trademarked phrase that refers to the IEEE 802.11x standard specifically – a modified version of the original standard.

That being said, most security and networking professionals use the term 802.1x for both wired and wireless networks if they are using WPA2-Enterprise security.

What is wired 802.1x?

Authenticating a wired network connection for 802.1x is a similar process to wireless. The wired network user must connect to the secure network from their device and present a signed certificate or valid credentials to authenticate their identity.

The primary difference is instead of establishing a secure connection with a wireless switch, your device must be Ethernet connected and authenticate to an 802.1x-capable switch. The device and RADIUS server establish trust over the wired connection and if the user is recognized, they will be authorized for secure network use.

How Secure is 802.1x?

When used correctly, it is the golden standard of network authentication security. It can prevent over-the-air credential theft attacks like Man-in-the-Middle attacks and Evil Twin proxies. It is much more secure than Pre-Shared Key networks, which are typically used in personal networks.

However, 802.1x security can vary greatly depending on two factors. The first variable occurs if end users are left to manually configure their devices. The configuration process requires high-level IT knowledge to understand and if one step is incorrect, they are left vulnerable to credential theft. We highly recommend using dedicated 802.1x onboarding software instead.

The second variable depends on whether an organization is using credential-based authentication or certificate-based authentication. Certificate-based EAP-TLS significantly reduces an organization’s risk for credential theft and is the most secure way to use 802.1x. Not only does it stop credentials from being sent over the air where they can be easily stolen, but it forces users to go through an enrollment/onboarding process that ensures their devices are configured correctly.

Is 802.1x encrypted?

Yes, 802.1x is encrypted.

802.1x WPA is generally reserved for personal networks, such as your home Wi-Fi, and runs on RC4-based TKIP (Temporal Key Integrity Protocol) encryption. It’s less secure than WPA2, but usually sufficient for home use.

802.1x WPA2 could utilize TKIP, but generally chooses AES (Advanced Encryption Standard), which is the most secure standard available. It is a little more difficult and costly to set up however, so it’s used in higher-stake environments like businesses.

The Components of 802.1x

There are just a few components that are needed to make 802.1x work. Realistically, if you already have access points and some spare server space, you possess all the hardware needed to make secure wireless happen. Sometimes you don’t even need the server; some access points come with built-in software that can operate 802.1x (though only for the smallest of small deployments).

Regardless of whether you purchase professional solutions or build one yourself from open source tools, the quality and ease of 802.1x is entirely a design aspect.

Client / Supplicant

In order for a device to participate in the 802.1x authentication, it must have a piece of software called a supplicant installed in the network stack. The supplicant is necessary as it will participate in the initial negotiation of the EAP transaction with the switch or controller and package up the user’s credentials in a manner compliant with 802.1x. If a client does not have a supplicant, the EAP frames sent from the switch or controller will be ignored and the switch will not be able to authenticate.

Fortunately, almost all devices we might expect to connect to a wireless network have a supplicant built-in. SecureW2 provides an 802.1x supplicant for devices that don’t have one natively.

Thankfully, the vast majority of device manufacturers have built-in support for 802.1x. The most common exceptions to this might be consumer gear, such as game consoles, entertainment devices or some printers. Generally speaking, these devices should be less than 10% of the devices on your network and are best treated as the exception rather than the focus.

Switch / Access Point / Controller

The switch or wireless controller plays an important role in the 802.1x transaction by acting as a ‘broker’ in the exchange. The client does not have network connectivity until there is a successful authentication, and the only communication is between the client and the switch in the 802.1x exchange.

The switch/controller initiates the exchange by sending an EAPOL-Start packet to the client when the client connects to the network. The client’s responses are forwarded to the correct RADIUS server based on the configuration in the Wireless Security Settings. When the authentication is complete, the switch/controller makes a decision whether to authorize the device for network access based on the user’s status and possibly the attributes contained in the Access_Accept packet sent from the RADIUS server.

If the RADIUS server sends an Access_Accept packet as a result of an authentication, it may contain certain attributes that provide the switch with information on how to connect the device on the network. Common attributes will specify which VLAN to assign a user to, or possibly a set of ACLs (Access Control Lists) the user should be given once connected. This is commonly called ‘User Based Policy Assignment’ as the RADIUS server is making the decision based on user credentials. Common use cases would be to push guest users to a ‘Guest VLAN’ and employees to an ‘Employee VLAN’.

RADIUS Server

The RADIUS server acts as the “security guard” of the network; as users connect to the network, the RADIUS authenticates their identity and authorizes them for network use. A user becomes authorized for network access after enrolling for a certificate from the PKI (Private Key Infrastructure) or confirming their credentials. Each time the user connects, the RADIUS confirms they have the correct certificate or credentials and prevents any unapproved users from accessing the network.

A key security mechanism to employ when using a RADIUS is server certificate validation. This guarantees that the user only connects to the network they intend to by configuring their device to confirm the identity of the RADIUS by checking the server certificate. If the certificate is not the one which the device is looking for, it will not send a certificate or credentials for authentication. This prevents users from falling victim to an Evil Twin proxy attack.

RADIUS servers can also be used to authenticate users from a different organization. Solutions like Eduroam use RADIUS servers as proxies (such as RADSEC). If a student visits a neighboring university, the RADIUS server can authenticate their status at their home university and grant them secure network access at the university they are currently visiting.

Why does 802.1x need a RADIUS server?

802.1x needs a RADIUS server because there needs to be a dedicated server to verify credentials. The authentication facet of 802.1x actually occurs at the RADIUS server. The server checks the directory of authorized users to confirm whether or not the client has permission to access the network and passes that information back to the controller/access point. Without a RADIUS server, authentication would have to occur at the access point (this would require some pretty powerful APs), such as in the case of PSK (pre-shared key) authentication.

Identity Store / Directory

The Identity Store refers to the entity in which usernames and passwords are stored. In most cases, this is Active Directory or potentially an LDAP server. Almost any RADIUS server can connect to your AD or LDAP to validate users. There are a few caveats when LDAP is used, specifically around how the passwords are hashed in the LDAP server. If your passwords are not stored in cleartext or an NTLM hash, you will need to choose your EAP methods carefully as certain methods may not be compatible, such as EAP-PEAP. This is not an issue caused by RADIUS servers, but rather from the password hash.

SecureW2 can help you set up SAML to authenticate users on any Identity Provider for Wi-Fi access. Here are guides to integrating with some popular products.

  • To set up SAML authentication within Google Apps, click here.
  • Configuring WPA2-Enterprise with Okta, click here.
  • For a guide on SAML Authentication using Shibboleth, click here.
  • To configure WPA2-Enterprise with ADFS, click here.

Developing a robust WPA2-Enterprise network requires additional tasks, such as setting up a PKI or CA (Certificate Authority) and seamlessly distributing certificates to users. But contrary to what you might think, you can make any of these upgrades without buying new hardware or making changes to the infrastructure. For example, rolling out guest access or changing the authentication method can be accomplished without additional infrastructure.

Recently, many institutions have been switching EAP methods from PEAP to EAP-TLS after seeing noticeable improvement in connection time and roaming ability. Improving the functionality of wireless networks can be gained without changing a single piece of hardware.

How Does 802.1x Authentication Work?

The authentication process is comprised of four steps: Initialization, Initiation, Negotiation, and Authentication.

Initialization

The Initialization step starts when the authenticator detects a new device and attempts to establish a connection. The authenticator port is set to an “unauthorized” state, meaning that only 802.1x traffic will be accepted and every other connection will be dropped.

Initiation

The authenticator starts transmitting EAP-Requests to the new device, which then sends EAP responses back to the authenticator. The response usually contains a way to identify the new device. The authenticator received the EAP response and relays it to the authentication server in a RADIUS access request packet.

Negotiation

Once the authentication server receives the request packet, it will respond with a RADIUS access challenge packet containing the approved EAP authentication method for the device. The authenticator will then pass on the challenge packet to the device to be authenticated.

Authentication

Once the EAP method is configured on the device, the authentication server will begin sending configuration profiles so the device will be authenticated. Once the process is complete, the port will be set to “authorized” and the device is configured to the 802.1x network.

Bonus: RADIUS Accounting

802.1x RADIUS accounting involves recording the information of devices that are authenticated to the 802.1x network and the session duration. The device information, usually the MAC address and port number, are sent in a packet to the accounting server when the session begins. The server will receive a message signalling the end of the session.

While this isn’t part of the 802.1x authentication process, we get a lot of questions about accounting, as RADIUS Servers are often referred to as AAA (Authentication, Authorization, Accounting) servers.

VLAN

A VLAN, or Virtual Local Area Network, is a method of configuring your network to emulate a LAN with all of the management and security benefits it provides.

Basically, VLANs are segmenting your network to organize the security rules found on a network. For example, the Open/Guest network is usually put in a different VLAN than the secure network. This helps to make sure that devices and network resources that are on one VLAN aren’t affected if anything bad happened on a seperate VLAN.

Digital certificates make VLAN assignment a snap because attributes can be encoded into the certificate that the RADIUS uses to authenticate. You could set up a policy so that anyone with the email domain “it.company.com” would be automatically assigned a different VLAN segment than “sales.company.com”.

MAC Authentication

MAC authentication, or MAC address authentication, is a simple security measure in which you create a list of approved MAC addresses that are allowed network access..

Unfortunately, it’s not difficult to spoof MAC addresses, so MAC authentication is rarely deployed on enterprise levels.

MAC RADIUS

MAC RADIUS is a form of MAC Authentication. Instead of using a credential or a certificate to authorize a device, the RADIUS confirms the MAC address and authenticates.

MAC Bypass

The primary use of MAC Bypass is to tie-in devices that don’t support 802.1x (like game consoles, printers, etc.) to your network. However, it’s still vulnerable, so it should be in a separate VLAN.

How do I Configure 802.1x on Devices?

Configure 802.1x on Windows

You can configure 802.1x on Windows OS devices in two ways: manually, or with device onboarding software.

Manually configuring a Windows device requires the user to set up a new wireless network, enter a network name, set the security type, adjust network settings, set the authentication method, and many more steps. While it’s certainly possible to complete this process accurately, it is highly complex and much more difficult than an onboarding software designed for efficiency.

The process for configuring Windows OS with SecureW2 requires the user to connect the onboarding SSID and open an internet browser. The user is sent to SecureW2’s JoinNow onboarding software. After clicking JoinNow, a graphic will indicate the progress of the configuration. The user will then be prompted to enter their credentials and the device will be authenticated and equipped with a certificate.

Configure 802.1x on macOS

For macOS, you can either manually configure or employ onboarding software to set up 802.1x.

In order to manually configure macOS, the end user needs to know how to create an enterprise profile, install a client security certificate, verify the certificate, and adjust the network settings. The process isn’t too difficult for someone with a background in IT, but it is risky for the average network user because of the high-level technical information involved with each step.

Downloading the SecureW2 JoinNow Suite for macOS enables automation so end users are not required to complete the process. The setup is similar to Windows OS; the end user starts by connecting to the onboarding SSID and opens a browser. After downloading the .DMG file and entering their credentials, the configuration process begins. The entire configuration and authentication requires only a few steps, allowing the end user to sit back while the device configures.

Configure 802.1x on Android

You are able to configure your Android for 802.1x in two ways: manually through the Wi-Fi settings or with device onboarding software.

Configuring manually via Wi-Fi settings requires you to create a network profile, configure Server Certificate Validation (which requires uploading the CA used on the RADIUS Server and the common name), and configuring the authentication method. If you use device onboarding software, all these steps are done by an application that can be downloaded from the Play Store that will configure your organization’s network settings for you.

Configure 802.1x on iOS

Configuring 802.1x authentication for iPhones requires you to either manually configure the device or use onboarding software.

Manual configuration means you need to create a network profile in the Wi-Fi settings and configure Server Certificate validation and the authentication method. The process is much simpler with onboarding software because SecureW2 can push a mobile config file to an iPhone device and configure the network settings automatically.

Configure 802.1x on Linux

Like other operating systems, there are two methods to configure 802.1x on Linux.

The manual configuration is relatively simple. Open up Network Manager, select Edit Connections, find your access point and click Edit. A new window will open up, choose the tab that says 802.1x settings and input the information of your network.

For one device, this is a straightforward process. If you need to onboard many devices (and users), you need SecureW2’s automatic device onboarding software. Click here to learn more.

802.1x vs WPA2-Enterprise

802.1x is an IEEE standard framework for encrypting and authenticating a user who is trying to associate to a wired or wireless network. WPA-Enterprise uses TKIP with RC4 encryption, while WPA2-Enterprise adds AES encryption.

Vulnerabilities in 802.1x

No security protocol is invulnerable, and 802.1x is not an exception.

Wireless 802.1x’s most common configurations are WPA-PSK (pre-shared key, also called WPA-Personal) and WPA or WPA2 Enterprise.

PSK is the simplest and the most vulnerable. A password is configured on the access point and distributed to users of the network. It’s intended for personal use, mostly in homes. It’s easily cracked with a run-of-the-mill brute force attack, and is also susceptible to all other common attacks.

Enterprise-level wireless networks are typically not compromised by brute force attacks because their network administrator will have mandated complex passwords and reset policies. Particular vulnerabilities vary depending on the authentication standard used by the enterprise network.

PEAP MSCHAPv2  was once the industry standard for WPA2-Enterprise networks, but it’s been cracked. There are still many organizations using this standard, despite the inherent vulnerabilities to over-the-air attacks.

EAP-TTLS/PAP is another common standard that is also very vulnerable to over-the-air attacks. It’s particularly weak because credentials are sent in clear text, so it’s a simple matter for hackers to intercept and steal. Further exacerbating the problem is the rising popularity of Cloud RADIUS servers. Many of them only support EAP-TTLS/PAP, so end users are forced to send their credentials in clear text over the internet.

The strongest WPA2-Enterprise standard is EAP-TLS. It relies on the asymmetrical cryptography of digital certificates for authentication, which renders it immune to over-the-air attacks. Even if a hacker intercepts the traffic, they will only harvest one half of the public-private key pair – which is useless without the other half.

Click here for more details on the steely defenses offered by EAP-TLS.

The Best 802.1x Enterprise Solution

The security of your network is the security of your organization. You wouldn’t leave your front door unlocked, so why would you leave your network unsecured?

SecureW2 is trusted by some of the biggest companies in the world to provide the highest level of security and peace of mind. Our software solutions can be integrated seamlessly into your current network infrastructure or stand on their own as a fully-managed network security service.

We have affordable options for organizations of any size. Check out our pricing to learn more.