EAP vs PEAP: Which Authentication Protocol Is More Secure?

Ensuring network users can securely authenticate to the wireless network is paramount to the overall safety and security of your organization. So many attacks are aimed at exploiting the authentication process. According to IBM’s X-Force Threat Intelligence Index, 35% of exploitation activity involves man-in-the-middle attacks.

The most widely used wireless network protocols today are the Extensible Authentication Protocols (EAP) used in WPA2-Enterprise. Utilizing an EAP authentication method ensures that users’ information is sent over-the-air using encryption and avoids interception.

Two of the most common EAP methods, EAP-TLS and PEAP-MSCHAPv2, are commonly used and accepted as secure authentication methods. This article will compare EAP and PEAP, explain the benefits of each protocol, and help you choose the best secure authentication method for your organization.

What is EAP?

EAP is an authentication framework that limits network access to only devices that have the required authentication key or password. It is compatible with different encryption methods, such as public key encryption, certificates, one-time passwords and smart cards.

EAP-TLS uses digital certificates for both devices and servers, requiring mutual authentication to verify each other’s identities.

What is PEAP?

PEAP is a protocol that builds on the EAP protocol by encapsulating it within a Transport Layer Security (TLS) tunnel. It ensures only authorized users have access to your network by acting as a protective layer around it.

PEAP-MSCHAPv2 is a network security protocol that combines Microsoft Challenge Handshake Authentication Protocol Version 2 and PEAP-TLS protocol. It encrypts credentials sent within the PEAP tunnel and performs a “handshake” with the corresponding RADIUS server to authenticate users.

While both EAP and PEAP authenticate users, they have different configuration requirements, security and risks associated with them.

Securely Configuring EAP-TLS vs PEAP-MSCHAPv2

While the configuration process for both EAP-TLS and PEAP-MSCHAPv2 is different, they have one thing in common: you should not allow users to manually configure their devices for network access.

When left to their own devices, the average network user has ample opportunities to misconfigure their device, leaving them open to man-in-the-middle attack (MITM) and evil twin attacks.

The process for EAP-TLS involves enrolling for and installing a digital certificate, and both protocols require server certificate validation configuration in order to remain effective against over-the-air credential theft attacks. And this hardly covers all the steps involved.

For the average network user, the process is complicated for both protocols, and manual configuration should be avoided at all costs.

To bypass the support tickets and security risks of manual configuration, it’s recommended that you deploy onboarding software to automatically configure new users.

Authentication With EAP-TLS and PEAP-MSCHAPv2

Both protocols are considered EAP methods, so they each send identifying information through the encrypted EAP tunnel. This encrypted tunnel prevents any outside user from reading the information being sent over-the-air.

However, the process for the end-user differs significantly between the two protocols.

With PEAP-MSCHAPv2, the user must enter their credentials to be sent to the RADIUS Server that verifies the credentials and authenticates them for network access.

EAP-TLS utilizes certificate-based authentication. Rather than sending credentials to the RADIUS server over-the-air, credentials are used for a one-time certificate enrollment, and the certificate is sent to the RADIUS server for authentication.

Over the course of the user’s lifetime with the organization, being able to auto-authenticate without having to memorize a password or update due to a password change policy is a huge benefit to the user experience.

While the information exchanged between the client device, access point (AP), and RADIUS server may be different between EAP-TLS and PEAP-MSCHAPv2, they both undergo a TLS Handshake. This is the communication process in which the server and client exchange identifying information. The two sides will verify one another’s identity, establish encryption algorithms, and agree on session keys to securely authenticate to the network.

The following image is from the Certified Wireless Security Professional Study Guide detailing the EAP-TLS authentication process.

The below image is from the Certified Wireless Security Professional Study Guide detailing the EAP-PEAP process.

The primary difference to highlight between the authentication processes above is the number of steps involved. The EAP-TLS process has almost half as many steps to authenticate.

For a single authenticating user, the time difference is nearly imperceptible. Where this difference of steps comes into play is during the event of a large authentication event.

If there is a situation where a large number of users are attempting to authenticate at the same time, the shortened process becomes a significant advantage. There’s a much smaller chance of a slowdown in authentication occurring.

Additionally, if your RADIUS is overloaded with authentication requests and does not have redundancy measures, your network could experience request denials and time-consuming delays.

For the sake of productivity, a shorter process can make a big difference.

The Risks of Each Authentication Method: EAP-TLS vs. PEAP-MSCHAPv2

WPA2 & WPA3 ENTERPRISE PROTOCOL	TUNNEL ENCRYPTION	CREDENTIAL METHOD	AUTH SPEED	DIRECTORY SUPPORT	CREDENTIALS
EAP-TLS	Mutual TLS Certificate-verified	Certificate No password transmitted	Fast ~12 steps	Universal	Passwordless
PEAP-MSCHAPv2	One-way TLS Server cert only	MD4 Hash Cryptographically broken	Slower ~22 steps	Active Directory AD only	Password

Comparing the security risks of certificate-based authentication and credential-based authentication reveals that certificates are far more secure than credentials.

Security Risks With Credentials and PEAP-MSCHAPv2

From an identity standpoint, credentials are not reliable. Stolen credentials can be used without a method for identifying if the authenticated user is actually who they claim to be.

Keep in mind that your network is comprised of multiple interconnected parts. A hacker can steal one set of credentials and begin digging deeper into your network from there.

Beyond identity issues, there are several attack methods for stealing valid credentials. A man-in-the-middle attack can be used to farm credentials from users authenticating to the incorrect network. A dictionary attack can be performed remotely by sending countless authentication requests until the correct password is sent. And phishing is a common psychological attack method to trick users into giving up their passwords.

This issue is worsened by the fact that the majority of people reuse their passwords. Capturing one set of credentials can be like snatching a master key that bad actors can use to access additional resources and wreak havoc on an organization-wide scale.

Overall, weak passwords and simple hacking attacks can threaten the integrity of a secure network.

Security Risks with Certificates and EAP-TLS

In contrast, certificates cannot be stolen over-the-air or used by an outside actor. They are protected with public key encryption and cannot be used by another device. Certificates cannot be transferred or stolen because they are linked to the identity of the device and user.

The only legitimate exploit to get around certificate security is a convoluted process where the hacker impersonates an employee and tricks a Public Key Infrastructure (PKI) vendor into distributing them a valid certificate. The process is extremely difficult and can be avoided by vetting your vendor and ensuring they use basic security best practices.

Add Device Context for Network Authentication With SecureW2

While both EAP methods protect the data being sent over-the-air, they differ in overall security, efficiency, and user experience.

EAP-TLS with certificate-based authentication is simply more secure and offers a superior user experience with benefits in efficiency and protection.

You get more context with digital certificates, increasing your capacity for device trust; a certificate can show you a number of factors, including a person’s role in the organization, their operating system, and when the operating system was last updated.

As an example, you can refer to the illustration below to see the information a certificate provides you as opposed to the information you can gather from credential-based authentication.

If you’re looking for the gold standard for authentication, SecureW2 offers a turnkey EAP-TLS solution that includes device onboarding software, Managed PKI Services, and a Cloud RADIUS Server.

Schedule a free demo to see if SecureW2’s solutions are a fit for your organization.