What Is Multi Factor Authentication (MFA)? Adaptive Strategies and Just-in-Time Access Explained

Multi factor authentication (MFA) solutions block around 7,000 attacks per second, and as identity threats accelerate, organizations are increasingly bolstering cyber defenses with MFA – 57% of businesses globally now use MFA, a 12% year-over-year increase.  

Still, MFA adoption varies widely across geographies, industries, and company size. While large enterprises average an 87% MFA adoption rate, nearly two-thirds of small and medium-sized businesses do not use MFA and have no plans to implement it. But adoption alone isn’t enough. Even organizations using MFA must contend with the reality that all multi factor authentication solutions are not created equal.  

We’ll walk through everything security teams need to know about MFA, discuss how it works, and explore how modern strategies like just-in-time access and network-layer enforcement ensure MFA effectively protects against evolving identity threats.  

What Does Multi Factor Authentication Mean?  

Multi factor authentication (MFA) is a security measure that requires users to present two or more pieces of evidence (factors) verifying their identities before granting them access to a system or application. These factors typically fall into three categories:  

• Something you know (a memorized password or PIN) 
• Something you have (like a code sent to your smartphone or another device) 
• Something you are (such as a fingerprint or face scan) 

Requiring multiple types of factors dramatically reduces the likelihood that a stolen credential alone could grant access. 

Multi Factor Authentication (MFA) vs. Two Factor Authentication (2FA) 

Though often used interchangeably, 2FA is narrower than MFA as it requires exactly two authentication factors. MFA, however, is broader – it can require two or more methods of verification and may dynamically adjust how many based on context or risk.  

Still, in most cases, MFA and 2FA boil down to the same takeaway in practice: you’ll need something more than a password to prove your identity.  

Why Is Multi Factor Authentication Important for Security?  

In the modern threat landscape, identity is the new perimeter – three out of every four attacks now rely on valid credentials. But as Chris Boehm, field CTO for the Americas at Zero Networks points out, “Networks were never designed to handle identity as a segmentation boundary. Attackers don’t need admin credentials to move laterally, they just need a foothold.” This is precisely why MFA is more critical than ever before for enhancing cyber defenses.  

According to CISA, organizations that implement MFA are 99% less likely to be hacked. This is because about 99% of the identity attacks that occur daily are password-based.   

Still, MFA alone isn’t a silver bullet. Attackers are adapting. Post-authentication attacks like token theft are on the rise, with an estimated 39,000 incidents now occurring daily. Meanwhile, strategies to bypass MFA entirely are picking up steam as MFA fatigue attacks persist and attacker-in-the-middle (AiTM) phishing schemes have risen 146% in the last year. To stay ahead of advanced identity threats, security teams will need to take a modern approach to MFA.  

Multi Factor Authentication Examples: How MFA Works  

There are many ways to implement MFA, depending on the use case, security needs, and user base. A few of the most common setups include:  

• Email or SMS verification: A code is sent to the user’s registered email address or phone number. It’s quick and simple, but vulnerable to SIM swapping, email compromise, or AiTM phishing, making this an increasingly risky approach to MFA.  
• Push notifications: An authentication prompt is sent to a trusted device via an app like Duo Mobile, Okta Verify, or Microsoft Authenticator; the user then approves or denies the request with a tap. This is one of the most common enterprise MFA methods.  
• Hardware keys: Devices like YubiKeys or smart cards offer physical proof of identity. These are highly resistant to phishing and credential theft but require far more logistical planning, making them difficult to effectively support at scale. 
• Biometric scans: Fingerprint or facial recognition provides a “something you are” factor that can’t be stolen like a password. Biometric MFA is fast and user-friendly, though it raises privacy and revocability concerns for some users.  

In most enterprise environments, MFA is integrated via identity providers (IdPs) such as Okta, Azure AD, or Ping Identity. These platforms enforce MFA during login workflows, typically at the time of user authentication or Single Sign-On (SSO). 

But this approach, while critical, doesn’t always translate into continuous access control. A user may be authenticated once, and then retain access to sensitive systems indefinitely unless additional controls are layered in. Service accounts, local admin accounts, and legacy apps may fall outside the IdP’s scope entirely, creating hidden exposure points across the network. 

Beyond the common MFA setups every user has likely seen, there are a few more niche forms of MFA that help overcome hidden risks and elevate authentication controls.  

Adaptive Multi Factor Authentication  

Adaptive MFA adjusts authentication requirements based on real-time risk signals, such as location, device, or behavior anomalies. For example: 

• If a login attempt originates from a familiar IP, a push notification may suffice. 
• If a request comes from an unexpected location or an unknown device, additional verification may be required. 

While adaptive MFA offers flexibility, its effectiveness depends on the granularity of data and the logic integrity. If misconfigured, it could block legitimate users – or let suspicious activity slip through. 

Just-in-Time (JIT) Access  

Just-in-time (JIT) access is a key security practice bolstering Zero Trust architectures. Instead of granting standing privileges, JIT enforces temporary, least-privilege access that is activated only when needed, and only after MFA approval. 

Just-in-time MFA dramatically reduces the attack surface, especially in environments where privileged access is rarely needed but frequently targeted by attackers.  

RDP Multi Factor Authentication  

Remote Desktop Protocol (RDP) is a popular vector for attackers because it’s often exposed and inadequately protected. Brute-force attacks against RDP ports remain one of the top techniques for initial access – particularly during ransomware attacks.  

Applying MFA to RDP sessions is critical, but not always straightforward – especially in hybrid environments or legacy systems where traditional MFA, which operates at layer 7, isn’t supported. Solutions that operate at the network layer, enforcing MFA before RDP sessions are even initiated, offer a powerful solution for RDP multi factor authentication.  

Benefits of Multi Factor Authentication  

Effective multi-factor authentication doesn’t just add a layer of protection, it reshapes how organizations think about identity, access, and risk. In the context of the current threat landscape, some of MFA’s core benefits include:  

Mitigate Credential-Based Attacks  

With phishing kits, credential stuffing tools, and infostealer malware widely available on the dark web, it’s only a matter of time before static credentials are compromised. In fact, brute force (such as password spraying or default credential compromises) and stolen credentials were the initial infection vectors for 47% of ransomware-related intrusions in 2024. MFA provides an essential second line of defense, requiring proof beyond what an attacker can easily buy, steal, or guess.  

Support Zero Trust Initiatives  

Zero Trust dictates that no user or device is inherently trusted; every access attempt must be verified continuously. MFA helps enforce this principle – when paired with microsegmentation and just-in-time access capabilities, MFA becomes a dynamic enforcer of least privilege, contributing to a resilient Zero Trust architecture.  

Reduce Compliance Risk and Lower Insurance Premiums  

Most major cybersecurity compliance frameworks explicitly require or strongly recommend MFA. By adopting robust MFA practices, organizations can more confidently meet regulatory demands and provide audit trails that demonstrate control effectiveness; this is especially critical in high-risk environments like finance and healthcare. Aside from regulatory demands, MFA is key to satisfying cyber insurance requirements as it has the potential to prevent over 90% of cyber insurance claims.  

Defend Remote Work Environments 

The rise of hybrid and remote work has dissolved traditional network perimeters. MFA plays a frontline role in securing this distributed workforce by validating identities in every session, regardless of geography or device. Combined with secure remote access tools, MFA ensures that remote users don’t become unintentional entry points for attackers. 

MFA Challenges: Limited Coverage, Legacy Gaps  

Despite being widely deployed and highly recommended across regulatory frameworks and industry-accepted best practices, multi-factor authentication isn’t universally foolproof. In many environments, MFA operates more like a patchwork of controls than a unified security strategy, leaving cracks for hackers to slip through.  

One of the most persistent issues is inconsistent MFA coverage across the IT ecosystem. While cloud applications and modern endpoints integrate easily with most MFA solutions, legacy systems, service accounts, OT/IoT devices, databases, and other non-SaaS assets often fall outside the bounds of enforcement. These unmanaged or hard-to-modernize assets are rarely protected by MFA, even though they frequently have privileged access.  

In fact, machine identities like service accounts make up over 70% of networked identities today, and they’re notoriously vulnerable. Only 2.6% of workload identity permissions are actually used and 51% of workload identities are completely inactive.  

In other words, as identity threats rise, MFA solutions that ignore large swaths of the infrastructure aren’t providing the comprehensive coverage necessary to address critical vulnerabilities. To overcome these challenges, accelerate Zero Trust initiatives, and proactively address evolving identity-based attacks, organizations need network-layer MFA that can:  

• Close all privileged ports and protocols by default, including RDP, SSH, WMI, RPC, and WinRM, granting just-in-time access after verification  
• Secure admin and service accounts, databases, OT/IoT systems, and other non-SaaS assets have been left uncovered by most MFA solutions  

Enforce JIT Access Controls Anywhere with Network-Layer MFA  

Unlike conventional MFA, which operates at the application level, Zero’s network-layer MFA seamlessly integrates into the network infrastructure at layer 3 of the OSI model, meaning it’s enforced long before a session reaches the application layer.  

So, rather than protecting SaaS applications, web portals, and little else, Zero Networks extends the power of MFA everywhere, enforcing authentication directly at the point of access.  

With Zero’s patented network-layer MFA, security teams can: 

• Easily protect RDP, SMB, SSH, WinRM, and more. According to Aaron Steinke, Head of Infrastructure at La Trobe Financial, his team was finally able to solve a persistent audit challenge with Zero Networks by applying MFA on high-risk protocols like RDP and SSH – without breaking legacy systems or introducing new points of failure. He said, “Every time the auditors come through (which is every five and a half minutes in a financial institution), we were getting asked why we’re not doing MFA on certain products and protocols. [Zero] has given us a way of implementing that.”  
• Keep privileged ports closed by default, only opening them when MFA is successfully completed 
• Ensure access is granted just in time, not permanently, then automatically revoked once the session ends  

This approach blends MFA and microsegment to create multi-factor segmentation, a strategy where MFA is enforced wherever and whenever a user or machine attempts to reach a protected resource. By layering network and identity segmentation with MFA, Zero closes the critical gaps that hackers exploit. Chris Turek, CIO at Evercore describes the combination this way:  

“Zero Networks is creating a new sphere of security capabilities. The combination of Zero’s network and identity segmentation capabilities redefines least privilege architecture, providing a level of protection that the market has never seen before. It allows security teams to control network device segmentation down to the port and protocol level and then layer complete control of user logon access by logon type – network, local, service, etc. As if that wasn’t enough, you can also add multi-factor authentication to any of those controls! You simply can’t do this using any other platform on the market today.”  

By combining JIT identity-based access controls, network-layer MFA, and microsegmentation, Zero dramatically reduces the attack surface while ensuring consistent enforcement across environments and airtight protection against lateral movement. Take a self-guided product tour to see how you can modernize your organization’s MFA strategy.