What Is Two-Factor Authentication (2FA)? Definition, Types, and Benefits

Passwords alone are no longer enough to protect your IT environment. With cyberattacks becoming more sophisticated, two-factor authentication (2FA) has become essential to today’s cybersecurity strategies. It verifies who users are by requiring two different forms of identification, adding an extra layer of security to your accounts and systems.

In this article, we’ll dive deep into what makes two-factor authentication a must-have for modern security, explore two-factor authentication types, and reveal how 2FA can enhance your cybersecurity.

What is two-factor authentication?

Two-factor authentication (2FA) is a subtype of multi-factor authentication (MFA) that specifically requires two distinct authentication factors to verify a user’s identity. These two factors typically combine:

• Something a user is / biometrics (fingerprint, iris, voice, etc.)
• Something a user knows (password, PIN, answer to a secret question, etc.)
• Something a user possesses (key, security token, bank card, smartphone, etc.)

By demanding different forms of identification, two-factor authentication technology significantly reduces the likelihood of unauthorized access, even if a password is compromised. It’s like having both a key and a PIN to open a vault — losing one won’t let the perpetrators crack the system.

What is NOT two-factor authentication?

Understanding what can’t be qualified as 2FA types is just as important as understanding the two-factor authentication mechanism. Here are a few examples:

• Additional security questions or images. A set of secret questions or images following the verification of credentials is an additional step, but not part of the two-factor authentication process. It simply represents another knowledge component and doesn’t meet the definition of 2FA. 
• Multiple passwords. Asking for two separate passwords also can’t be considered 2FA since it’s still a single factor (something you know).
• Using the same device for both factors. Receiving a code on the same device used for login doesn’t provide true two-factor security, as it doesn’t effectively separate the factors.

Scenarios described above are examples of so-called strong authentication.

How does two-factor authentication work?

2FA isn’t one-size-fits-all —it offers a variety of methods to suit different security needs. The basic process, though, is as follows:

1. Login attempt. The user enters their username and password as the first authentication factor.
2. Second factor prompt. Once the password is verified and approved, the system requests a second form of authentication. This could be a one-time code, a push notification, biometric verification, etc.
3. Verification of the second factor. The user provides the second factor.
4. Access granted. The user can access the account or system if both factors are authenticated.

By requiring these distinct steps, 2FA ensures that even if attackers compromise one of the factors (like a password), they still won’t be able to access the account.

How to implement a two-factor authentication system?

Implementing a robust 2FA system requires careful planning and dedicated tools. You must design an authentication process that will be secure yet user-friendly. There are multiple 2FA options that cater to different user preferences.

Ensure that the second factor is delivered over secure channels. Avoid relying solely on SMS for sensitive applications, as it’s vulnerable to interception. To prevent breaches, you also need to encrypt all authentication-related data during transmission and storage.

Consider deploying cybersecurity solutions that monitor for unusual authentication attempts and trigger alerts when anomalies are detected. It’s also critical to protect the first authentication factor — credentials — with password vaults or dedicated password management systems.When it comes to choosing the right types of 2FA, it’s important to be knowledgeable about the most popular and widely used ones in IT. Let’s look at each of these two-factor authentication methods in detail.

What are the main types of 2FA?

The most common types of two-factor authentication include:

Hardware tokens

Physical authentication devices provide one of the most robust forms of 2FA, requiring the user to have the token physically. A security token is a device that contains software that can generate validation codes. There are two types of tokens:

• Connected tokens are generated when the device is connected to the target endpoint.
• Disconnected tokens are generated independently, without the need to connect the device with the endpoint.

One of the main drawbacks of using security tokens is a certain level of inconvenience. There are too many things to take care of, such as the production, management, maintenance, and replacement of numerous devices. Not to mention that users need to carry along an extra device every time they want to access a protected endpoint.

Mobile-delivered tokens can be seen as a way out. In contrast to hardware tokens, this method involves the thing almost everyone always has at hand: a smartphone.

Today, mobile-delivered tokens are one of the most popular and widely used methods of 2FA. Usually, a user requesting access to a protected endpoint or data receives a confirmation code via an SMS. One of the most widespread examples of using mobile-delivered tokens is receiving an SMS code to log into your bank account.

While convenient, this approach also has several drawbacks:

• Token generation — tokens need to be generated dynamically, and the security of the process will heavily depend on the generation algorithm. Passcodes should be valid only for a limited time, expire after the first use, and constantly change to avoid blind guessing.
• Code delivery — the security of message delivery fully depends on the mobile operator’s operational security. Techniques like SIM swapping or SMS spoofing can provide cyber criminals with the knowledge they need to get access to protected assets.
• Network connection — the user should be connected to the mobile network in order to receive a verification code via a smartphone.

Time-based one-time passwords

A time-based one-time password algorithm, or TOTP, addresses the drawbacks of mobile-delivered tokens. TOTP codes are generated locally on the user’s device using an authenticator app such as Google Authenticator or Microsoft Authenticator. If the provided verification code matches, access is granted.

The benefits of TOTP include:

• Offline work — you do not need a network connection to access the code via your device. The app automatically generates codes at fixed intervals, typically every 30 seconds. 
• Reliability —  since TOTP doesn’t depend on external communication, it offers a more secure authentication procedure.

Such codes are harder to intercept than SMS, making them a more reliable option. Also, mobile authenticating apps allow users to access their passcode at any time, even without a cellular or wifi connection. 

Push notifications

Push notification-based 2FA is another secure and user-friendly method that involves sending a notification to a user’s registered device via push notification 2FA services like Microsoft Azure Notification Hubs, Firebase Cloud Messaging (for Android), and Apple Push Notification Service (for iOS).

The notification includes authentication details (e.g., app name, location, time) and an “Approve” or “Deny” option.

Advantages of push notification-based 2FA include:

• Convenience — users can authenticate with a simple tap, avoiding the need to manually input a code.
• Enhanced security — this method eliminates phishing risks associated with manually entered codes.
• Real-time alerts — users are immediately notified of suspicious login attempts and can deny unauthorized access.
• Device binding — push notifications are sent only to registered devices.

All these two-factor authentication examples include their own unique benefits and drawbacks, yet they serve the same purpose: to protect your critical systems and data from unauthorized access. 

What threats does two-factor authentication minimize?

By requiring two distinct forms of identification, two-factor authentication (2FA) can help you protect your organization against:

Phishing attacks

Attackers often deceive users into providing login credentials through fake websites or emails. With 2FA, even if the password is compromised, the attacker can’t access the account without the second factor. This extra layer acts as a barrier against unauthorized access via phishing.

Credential stuffing

Credential stuffing is a common attack method where cybercriminals exploit stolen credentials obtained from previous data breaches to try to access accounts on other platforms. 2FA renders such attacks ineffective.

Man-in-the-middle attacks

In scenarios where attackers intercept login credentials during transmission (e.g., over unsecured networks or via compromised systems), 2FA ensures that the stolen credentials alone are insufficient to gain access. 

Password spraying attacks

During password spraying attacks, cybercriminals often target a large number of accounts by trying a small number of commonly used passwords. 2FA creates a bottleneck, as attackers won’t be able to provide the second authentication factor.

Brute-force attacks

Attackers still extensively use automated tools to guess passwords by trying millions of combinations. If they eventually crack a weak or reused password, 2FA will prevent further intrusion.

Insider threats

Employees or trusted individuals can accidentally compromise your accounts. For example, they may reuse the same password across multiple accounts, making all of them vulnerable even if only one account is compromised. 2FA mitigates this risk by requiring a second factor unique to each platform.

Below, we provide recent incidents that could have been prevented by using 2FA.

When organizations fail to implement 2FA, the consequences can be severe, as demonstrated by these recent incidents. These examples highlight the importance of robust security measures to protect sensitive data. However, there are additional reasons 2FA is such an essential tool in cybersecurity.

Why use two-factor authentication?

For many businesses, 2FA isn’t just a recommended practice but a mandatory requirement. For example, PCI DSS Requirement 8.4 (version 4.0) mandates the use of two-factor authentication for all accounts accessing sensitive card data, both remotely from outside the network and within the trusted network. NIST also requires the use of 2FA.

According to cybersecurity best practices, two-factor authentication should be used in these scenarios:

While 2FA can provide a critical extra layer of protection, implementing it effectively across an organization is not without its challenges. Below, we outline some common hurdles organizations may face when integrating 2FA into their security strategies.

Challenges of implementing 2FA

These are some of the common challenges organizations face when implementing two-factor authentication:

• Employee resistance — users might find 2FA inconvenient or time-consuming, especially if it requires additional steps during the login process. This resistance can lead to non-compliance with your policies or attempts to bypass the system.
• High cost of implementation — deploying 2FA across your organization can require significant investments in terms of hardware (e.g., token generators), software solutions, and ongoing maintenance.
• Compatibility issues — legacy systems or older applications may not support 2FA, requiring additional upgrades or custom integrations, which can be complex and resource-intensive.
• Administrative burden — managing and maintaining 2FA systems, such as handling lost devices, resetting authentication tokens, or resolving user issues, can create an additional workload for IT departments.

Syteca enables organizations to overcome the hurdles of implementing 2FA and enjoy enhanced security through a cost-effective, reliable, and easy-to-use solution.

Benefit from Syteca’s free 2FA solution

Syteca is a comprehensive cybersecurity platform that delivers built-in two-factor authentication as part of its identity and access management solutions.

Our 2FA tool uses centrally managed TOTP-based authentication as the second authentication factor. Verification codes can be sent to Android and iOS devices via Google Authenticator or Microsoft Authenticator apps. You can enable the 2FA functionality on any Windows or Linux server or endpoint with a Syteca software agent installed.

In addition to 2FA, Syteca enhances the security of the first authentication factor (password) with its password manager. Syteca ensures the secure storage of encrypted credentials, password rotation, and safe sharing of credentials within teams.

Syteca is designed for quick deployment and integration into your existing IT environments, so initial installation doesn’t require too much time or effort. It can be deployed on-premises, in the cloud, or in hybrid work environments without interfering with system performance.

Conclusion

Two-factor authentication is essential for ensuring a proper level of user identity verification. By requiring a second form of authentication, 2FA significantly reduces the risk of unauthorized users gaining access to your sensitive systems or data, even if login credentials are compromised.

With Syteca’s 2FA, you can protect your critical systems and endpoints, limit access to valuable data, and add one more layer of identity verification to the login process for privileged users, remote employees, and third parties. You can also incorporate other advanced Syteca features to reduce insider threats and operational risks!