Despite widespread awareness of cybersecurity threats, many organizations continue to operate Virtual Private Network (VPN) infrastructure with single-factor authentication, creating a dangerous vulnerability that attackers actively exploit. Recent data reveals that 56 percent of companies experienced a VPN-exploited breach in the past year, yet approximately 33 percent of VPN users still lack multi-factor authentication (MFA) protection. The disconnect between the recognized risks and actual security practices represents one of the most significant oversights in modern enterprise security posture. This comprehensive analysis examines why implementing MFA on VPN accounts is no longer optional but rather an essential, non-negotiable component of any organization’s security infrastructure, exploring the threat landscape, implementation strategies, regulatory mandates, and practical deployment considerations that security leaders must understand to protect their most critical access vectors.
The Vulnerability Landscape of VPN-Only Authentication
Virtual Private Networks have long served as the foundation for secure remote access, yet their architecture contains a fundamental weakness that becomes particularly dangerous when protected only by passwords. Although VPNs encrypt traffic and thus provide a certain level of security, they are not an all-encompassing cybersecurity solution. The core vulnerability lies in the authentication mechanism at the VPN gateway, which concentrates significant risk in a single chokepoint that attackers actively target. When a VPN connection relies solely on username and password credentials, the system becomes vulnerable to the full spectrum of password-based attacks that have proven devastatingly effective in the modern threat landscape.
Passwords alone have become demonstrably insufficient for protecting VPN access because attackers have developed sophisticated techniques to obtain and exploit them. Even strong passwords are susceptible to theft, phishing schemes, and brute force attacks. Once compromised, they can grant attackers unrestricted access to sensitive systems via the VPN, potentially leading to data breaches, financial losses, or reputational damage. The problem has intensified as credential theft has become industrialized, with billions of credentials available on the dark web and attackers employing automated tools to test compromised passwords across multiple VPN implementations. In fact, the 2024 Verizon Data Breach Investigations Report documented that use of stolen credentials remains the most common cause of data breaches, accounting for over 24% of hacking-related incidents. This widespread availability of compromised credentials, combined with common user behaviors like password reuse and weakness, creates an environment where password-only VPN authentication provides minimal actual protection against determined attackers.
VPNs are particularly attractive targets for attackers because of their privileged position in network architecture. A compromised VPN gateway provides what amounts to a skeleton key to the entire network, eliminating the need for lateral movement or complex exploitation chains. As a result, both initial access brokers and ransomware groups have systematically targeted VPN infrastructure, with VPNs and firewalls accounting for 44% of all zero-day exploits in 2024. State-sponsored actors, particularly Chinese groups, have demonstrated the sophistication and persistence with which they target VPN infrastructure, deploying custom malware on over 20,000 devices worldwide, including critical infrastructure systems. The commercial threat landscape is similarly dire, with multiple vendors experiencing critical vulnerabilities that have been actively exploited in the wild for extended periods before discovery.
Understanding Multi-Factor Authentication and Its Components
Multi-factor authentication operates on a straightforward but powerful principle: authentication should require proof of identity from at least two different categories of evidence, making it dramatically more difficult for attackers to gain unauthorized access even when they possess one factor. MFA requires users to provide at least two distinct factors to prove they are who they’re supposed to be before they’re granted VPN access to sensitive systems and data. By adding a second factor of authentication to secure VPN connections, the solution dramatically reduces unauthorized access risks because the second factor requires users to prove they are who they say they are by presenting additional proof beyond their password.
The authentication factors used in MFA fall into three fundamental categories, each representing a different type of proof of identity. The first category comprises something you know, such as a password, PIN, security question, or personal identification number. While these knowledge factors remain essential to most authentication systems, they alone are insufficient because they are susceptible to theft, guessing, and social engineering. The second category encompasses something you have, which typically includes a smartphone, hardware token, security token, or smart card. Possession factors work because they require the user to have a specific physical or virtual device in their control at the moment of authentication. The third category involves something you are, referring to biometric data such as fingerprints, facial recognition, voice recognition, or iris scans. Inherence factors are generally considered the most secure because they leverage biological characteristics that are extremely difficult to forge or steal, though they may present challenges in certain environments or for users with accessibility needs.
For VPN implementations specifically, popular MFA methods include SMS codes, authenticator apps, hardware tokens, and push notifications. SMS-based one-time passcodes (OTPs) represent a widely deployed method where a temporary code is sent to the user’s registered phone number through text message, though security experts increasingly warn against relying on SMS due to vulnerabilities including SIM-swapping attacks and interception. Authenticator applications such as Google Authenticator, Microsoft Authenticator, or Duo generate time-based one-time passwords (TOTP) that change every 30 seconds using cryptographic algorithms on the user’s device without requiring internet access. These software-based solutions provide significantly better security than SMS while maintaining reasonable user convenience. Hardware tokens, such as YubiKeys or RSA tokens, provide the highest security for possession-based factors by storing cryptographic keys on a physical device that the user must possess. Push notifications send an approval prompt to the user’s registered mobile device, where they must actively approve the authentication attempt, combining possession (the device) with user interaction. Biometric authentication using fingerprint or facial recognition offers the advantage of combining possession factors (the registered device) with inherence factors (biological characteristics), though implementation varies by platform and device type.
VPN Security Breaches: From Credential Theft to Network Compromise
Real-world VPN compromises demonstrate with stark clarity how a single set of stolen credentials can trigger a cascading series of events leading to complete network compromise, data exfiltration, and ransomware deployment. A major manufacturing company fell victim to a swift and devastating ransomware attack after threat actors gained access using just one set of stolen VPN credentials. The attack, carried out by the cybercrime group Ignoble Scorpius, illustrates the attack pattern that has become disturbingly common in 2025. The breach began when an employee received a deceptive voice phishing call, where the caller pretended to be from the company’s IT help desk and convinced the employee to enter their VPN login information on a counterfeit website. With these stolen credentials, attackers slipped inside the network undetected and quickly elevated their user privileges through a DCSync attack on a domain controller to harvest additional high-level credentials.
Once inside the network, attackers moved through the infrastructure with systematic precision, using Remote Desktop and SMB protocols combined with common system tools such as Advanced IP Scanner to map the network and identify high-value servers. They installed AnyDesk and a custom remote access Trojan on a domain controller, configuring it as a scheduled task to ensure persistence across system reboots. A second domain controller was then compromised, exposing the entire NTDS.dit database of password hashes, and over 400 GB of sensitive data was siphoned off using a renamed rclone utility. Before launching the ransomware, attackers ran CCleaner to wipe forensic logs, ensuring their activities would be difficult to trace. The final phase involved hundreds of virtual machines across roughly 60 VMware ESXi hosts being encrypted almost simultaneously using the BlackSuit ransomware payload, bringing production lines to a grinding halt and causing significant financial and operational damage. The response team subsequently mandated that multi-factor authentication be implemented for all remote logins, a security measure that could have prevented this entire attack sequence had it been in place from the beginning.
The SonicWall incidents of October 2025 provide another alarming example of how widespread VPN compromises can propagate across multiple organizations simultaneously. Cybersecurity company Huntress warned of “widespread compromise” of SonicWall SSL VPN devices, with threat actors authenticating into multiple accounts rapidly across compromised devices, suggesting they controlled valid credentials rather than relying on brute-forcing. A significant portion of the activity commenced on October 4, 2025, with more than 100 SonicWall SSL VPN accounts across 16 customer accounts having been impacted. The incident was linked to unauthorized exposure of firewall configuration backup files stored in MySonicWall accounts, which revealed sensitive information that could be leveraged by threat actors to exploit and gain access to organizations’ networks. These configuration files store critical information such as user, group, and domain settings, DNS and log settings, and certificates that enable attackers to understand network architecture and identify high-value targets.
The pattern of exploits targeting VPN infrastructure reveals a troubling trend in how attackers prioritize their efforts. While the total number of detected zero-day exploits fluctuates annually, the overall volume of attacks has stabilized at a new, elevated baseline far exceeding levels seen before 2021, with 75 zero-days actively exploited in the wild in 2024. Most significantly, attacks targeting enterprise-specific technologies skyrocketed, accounting for 44% of all zero-day exploits, with particular focus on security and networking products like VPNs and firewalls. The concentration of attack efforts on VPN and firewall infrastructure reflects a strategic decision by attackers: these devices are internet-facing, highly privileged entry points where a single compromise can provide gateway access to an entire corporate network. Recent vulnerability analysis of edge devices demonstrates that the most frequently exploited vulnerabilities in 2024 were found in network edge devices like VPNs and firewalls.
MFA Implementation for VPN Security
Implementing MFA for VPN access requires careful consideration of technical architecture, integration approaches, and user experience factors that will determine both the effectiveness and adoption success of the deployment. When implementing VPN MFA in an on-premise Active Directory environment, organizations should seek solutions that offer flexibility across authentication choices, improve user accountability, and provide clear visibility into access attempts. Multiple technical approaches exist for integrating MFA with VPN infrastructure, each with particular advantages and integration requirements that must be evaluated based on the organization’s existing network topology and authentication systems.
The RADIUS Challenge approach represents one of the primary methods for implementing MFA for VPN connections, recommended particularly for VPN clients that support this feature. This method prompts users to enter an OTP code after providing their credentials, ensuring that the first factor (password) and second factor (one-time password) are both validated before VPN access is granted. To implement this approach, organizations must install the latest UserLock NPS agent on their Network Policy Server, configure the VPN server to use NPS for RADIUS authentication and accounting, and set “MfaVpnChallenge” to True in the authentication system’s advanced settings. This approach provides seamless user experience for clients supporting this feature and works with popular VPN solutions including OpenVPN, Palo Alto, Fortinet, and Pulse Secure Connect Secure SSL.
The Microsoft RRAS (Routing and Remote Access Service) method provides an alternative implementation path for organizations using Microsoft infrastructure. This approach involves installing MFA software on the RRAS server, configuring RRAS for local authentication, and setting up the MFA solution to intercept logins and prompt for additional authentication factors. For Windows VPN connections specifically, organizations can install specialized VPN Connect tools on end-user computers, offering an improved user experience for users authenticating to VPN sessions with MFA and enabling easy MFA enrollment via VPN connection.
Cloud-based approaches to VPN MFA have gained significant prominence as organizations migrate infrastructure to cloud environments. Microsoft Entra ID provides capabilities for enabling multifactor authentication for point-to-site VPN users, with options to configure MFA on a per-user basis or leverage MFA via Conditional Access policies. The per-user approach enables MFA at no additional cost, where users are prompted for second factor authentication against all applications tied to the Microsoft Entra tenant. Alternatively, Conditional Access allows finer-grained control over when a second factor should be required, permitting assignment of MFA specifically to VPN while excluding other applications tied to the tenant. This flexibility enables organizations to implement MFA policies tailored to their specific risk profile and user populations.
Azure VPN Gateway supports integration with Microsoft Entra ID authentication, enabling organizations to configure Conditional Access policies that enforce MFA before establishing the VPN tunnel. This approach integrates authentication with Microsoft Entra ID for single sign-on while enforcing Conditional Access policies such as MFA, device compliance, and named location restrictions. The platform provides continuous access evaluation capabilities that can revoke VPN tunnel access if risk conditions change during an active session, enabling real-time response to detected threats rather than relying only on point-in-time authentication checks.
Organizations must also consider backup authentication methods to account for scenarios where users lose access to their primary authentication factors, such as when a smartphone is lost, stolen, or unavailable due to lack of network connectivity. Effective backup authentication uses email and phone attributes stored in the organization’s user directory to send one-time passcodes through SMS, voice, or email. By implementing backup authentication methods, organizations can maintain security while reducing the disruption caused by device loss or unavailability, thereby supporting user adoption and reducing support burden on IT teams.
Regulatory Compliance and Cyber Insurance Requirements
The regulatory environment surrounding VPN security has fundamentally shifted, with major compliance frameworks and government mandates now explicitly requiring or strongly recommending MFA for remote access. This transition from optional best practice to mandatory compliance requirement has profound implications for organizations across all sectors and sizes. Health Insurance Portability and Accountability Act (HIPAA) requirements mandate access controls like MFA to protect electronic protected health information (ePHI). The Payment Card Industry Data Security Standard (PCI DSS) requires MFA for users who access cardholder data environments (CDE). The Federal Trade Commission (FTC) Safeguards Rule mandates that financial institutions use MFA to secure customer data. NIST 800-171 and the Cybersecurity Maturity Model Certification (CMMC) set specific MFA expectations for federal contractors managing Controlled Unclassified Information (CUI).
The Internal Revenue Service (IRS) publication 1075, which governs tax information security, requires multi-factor authentication for “all remote network access to privileged and non-privileged accounts for information systems that receive, process, store or transmit FTI” (Federal Tax Information). This requirement must use at least two of the following types of authentication: something you know (password, PIN, challenge question), something you have (hardware or software token), or something you are (biometric data). The regulation explicitly prohibits satisfying MFA requirements by using two factors from the same category, such as two different passwords, ensuring that organizations implement genuinely diverse authentication factors.
Beyond regulatory requirements, cyber insurance has emerged as a powerful driver forcing MFA adoption across business sectors. Cyber insurance carriers have made it clear that MFA is now table stakes for coverage, with many insurers treating MFA as a simple “yes or no” question on application forms. Either organizations have MFA implemented for remote access and critical accounts, or they face difficulty qualifying for insurance, higher premiums, or exclusions that eliminate coverage for certain types of incidents. The underwriting shift reflects insurers’ assessment that the risk of compromise without MFA is now so high that it exceeds their appetite for risk at standard rates. Insurers want companies to have not only a VPN but also Multi-Factor Authentication (MFA) for remote network access and other key areas such as privileged user access or access to back-ups and cloud storage. This requirement creates a powerful business case for MFA implementation beyond purely security considerations, as lack of MFA can now result in inability to obtain cyber insurance coverage, loss of competitive insurance pricing, or gaps in cyber policy exclusions.
The compliance landscape reflects a broader consensus across government agencies, regulatory bodies, and industry leaders that single-factor authentication for remote access is no longer acceptable security practice. The shift is particularly pronounced in sectors handling sensitive data, such as healthcare and finance, where regulatory frameworks have the most explicit and stringent requirements. However, the trend extends across all sectors, with federal agencies, state governments, and private industries adopting policies requiring MFA for remote access. Data demonstrates that 72% of federal agencies in the U.S. have now implemented MFA, a substantial improvement driven by increasing cyber regulations and executive orders on cybersecurity. This public sector adoption establishes a benchmark and sets expectations that private sector organizations are increasingly expected to meet or exceed.
Advanced MFA Approaches and Emerging Technologies
While traditional MFA methods using SMS codes, authenticator applications, and push notifications provide substantial security improvements compared to passwords alone, the threat landscape continues evolving in ways that demand increasingly sophisticated authentication approaches. Phishing-resistant MFA has emerged as the gold standard security model, recognized by government agencies including the Office of Management and Budget (OMB), CISA (Cybersecurity and Infrastructure Security Agency), and NIST as the most robust approach to authentication. Unlike traditional MFA methods that rely on codes or secrets that could theoretically be intercepted or phished, phishing-resistant MFA does not use shared secrets at any point in the login process, eliminating the attacker’s ability to intercept and replay access credentials.
Phishing-resistant MFA is based on public/private key cryptography and follows guidelines published by the OMB in its M-22-09 Federal Zero Trust Strategy memorandum and requirements for “verifier impersonation resistance” outlined by NIST in SP 800-63-3. The most common phishing-resistant authentication methods include FIDO (Fast Identity Online) standards-based approaches and public key infrastructure (PKI)-based methods. These approaches use strong possession factors in the form of a private cryptographic key embedded at the hardware level in a user-owned device, combined with strong user inherence factors such as touch or facial recognition. Critically, the backend authentication process does not require or store a shared secret, fundamentally changing the attack surface compared to traditional MFA approaches.
Hardware security keys such as YubiKeys exemplify FIDO2-compliant phishing-resistant authentication, requiring physical possession of the key and resisting phishing attacks through the use of cryptographic protocols rather than shared secrets. These keys have demonstrated remarkable effectiveness in real-world deployments; Cloudflare, a leading security company, eliminated weaker MFA methods and enforced exclusive use of hardware security keys across the organization after observing an increase in sophisticated social engineering attempts. This decision has proven successful in preventing account compromises even in the face of sophisticated phishing campaigns.
Passwordless authentication represents another evolutionary step in authentication technology, moving away from traditional passwords to more secure and user-friendly authentication methods. With passwordless authentication, users no longer need to worry about remembering passwords or susceptible to phishing attacks targeting password entry. Biometric methods such as fingerprint scanning or facial recognition offer fast, reliable logins that are difficult for attackers to replicate. Magic links sent to email provide quick, password-free login capability. Hardware tokens offer robust security features without requiring password management. Single sign-on (SSO) reduces the number of passwords users need to remember. By replacing traditional passwords with these innovative methods, organizations enhance both security and user experience.
Adaptive authentication, sometimes called risk-based authentication, represents a sophisticated approach that dynamically adjusts authentication requirements based on the perceived risk indicated by user behavior and contextual factors. Adaptive authentication takes into account various data points to make authentication decisions, including device type, location, IP address, time of access, and behavior patterns such as typing speed or mouse movement. If a user logs in from the same location every day at roughly the same time on their usual device, adaptive MFA might grant access without requiring an additional authentication factor. However, if a user suddenly tries to access systems from a location far away, at an unusual time, from an unrecognized device, or on an unfamiliar network, the system might request an additional factor. This approach provides stronger security than static authentication methods while reducing MFA fatigue by minimizing unnecessary authentication prompts for legitimate users engaging in normal behavior.
Zero Trust Network Access (ZTNA) represents a broader architectural approach that integrates MFA with zero trust principles, fundamentally redefining how organizations approach network security. Zero Trust security means that no one is trusted by default from inside or outside the network, and verification is required from everyone trying to gain access to resources on the network. MFA is also a core value of Zero Trust security, requiring more than one piece of evidence to authenticate a user, ensuring that just entering a password is not enough to gain access. Zero Trust architecture provides continuous validation of identity and integrates contextual factors such as location, device health, and user behavior into access decisions. By integrating MFA with zero trust principles, organizations enforce least-privileged access where users have only the access necessary for their specific roles, minimizing each user’s exposure to sensitive parts of the network. VPNs are not well-suited for least-privilege approaches to authorization because logging into a VPN traditionally grants a user access to the whole connected network, which is why ZTNA approaches that enforce identity-based, application-specific access represent a superior security model for modern distributed environments.
Cost Analysis and Return on Investment
Organizations evaluating MFA implementation frequently encounter cost concerns, yet comprehensive analysis reveals that the return on investment substantially outweighs initial and ongoing expenses when compared to the costs of security breaches. Understanding the full cost of ownership and the financial impact of prevented breaches is essential for making sound business decisions about MFA implementation. Initial setup costs for MFA include licensing fees for MFA solutions, which may charge per-user or per-device fees depending on the provider. Deployment expenses for IT teams are required to configure the MFA system, test authentication methods across multiple devices and platforms, and troubleshoot issues, potentially requiring additional IT team members or capacity reallocation. Integration with existing security infrastructure may require customization to ensure compatibility with current firewalls, VPNs, and Single Sign-On (SSO) systems.
Hardware and software investments vary depending on the MFA approach selected. Physical security keys such as YubiKeys or RSA tokens provide high security but come with additional costs for procurement and distribution to all users requiring secure access. Software-based authentication applications such as Google Authenticator or Microsoft Authenticator offer cost-effective alternatives to hardware tokens by leveraging smartphone applications to generate authentication codes. Infrastructure upgrades may be required in some environments to support enhanced authentication capabilities, including upgrades to authentication servers or implementation of new security policies and management tools.
Ongoing maintenance costs ensure continued protection against cyber threats following initial deployment. Regular updates and security patches must be applied promptly to address emerging vulnerabilities in MFA software and systems. Technical support and troubleshooting are necessary as employees encounter authentication issues or need device replacements. User management and compliance verification ensure MFA is consistently applied across all access points and meets industry regulations. Employee education on MFA best practices helps ensure staff understand the importance of MFA and use it properly. Helpdesk resources for authentication issues, including password resets and lost authentication devices, represent an ongoing support requirement.
The financial case for MFA becomes compelling when compared to the costs of security breaches. Microsoft research demonstrates that MFA implementation offers outstanding protection, with over 99.99% of MFA-enabled accounts remaining secure during investigation periods. Moreover, MFA reduces the risk of compromise by 99.22% across the entire population and by 98.56% even in cases where credentials have been leaked. These protection rates translate directly into breach prevention, which is economically significant given that the average cost of a single data breach exceeds $3 million. When companies suffer breaches, the costs extend far beyond direct financial losses, including regulatory fines, business interruption, reputational damage, and customer notification expenses. In contrast, implementing MFA requires an investment that is modest compared to the financial exposure prevented by the protection it provides.
Sixty-two percent of breaches could have been prevented by MFA, according to security research. When evaluated from a cost-benefit perspective, this statistic means that implementing MFA could prevent nearly two-thirds of security incidents that organizations currently experience. Considering that organizations typically experience multiple security incidents annually, the prevention value of MFA becomes substantial. Cyber insurance companies have incorporated this analysis into their pricing models, with many carriers now offering reduced premiums or only offering coverage to organizations with MFA implemented. This creates a direct financial benefit from MFA implementation through improved cyber insurance terms and availability.
The time-to-value for MFA implementation depends heavily on the approach selected and the organization’s existing infrastructure. Cloud-based MFA solutions typically provide faster deployment times since they do not require hardware or software installation, while on-premises solutions tend to consume more time and resources to get up and running. Organizations implementing MFA should conduct proof-of-concept pilots with a small group of users before full deployment, allowing them to gather valuable feedback on what works and what needs adjustment before scaling to the entire organization. A phased rollout approach starting with pilot users, then expanding through departments or roles in stages, minimizes disruption while allowing the organization to refine processes and gather feedback.
User Adoption, Training, and Change Management
The technical implementation of MFA represents only part of the challenge; achieving widespread user adoption and maintaining strong security practices requires thoughtful change management, comprehensive training, and attention to user experience factors that determine whether employees embrace or circumvent security controls. User resistance to MFA can stem from multiple factors, creating adoption barriers that organizations must actively address rather than assume will resolve naturally. Several users perceive the extra step involved in authentication as a disturbance that causes delays in their routine work and reduces their productivity. Users may lack full understanding of MFA’s significance or fail to appreciate how it adds security to their accounts and data. Some users express concerns about whether they are providing additional personal information or whether MFA methods in use are actually secure. Technological challenges emerge when the setup and usage process is not clearly described or sufficiently user-friendly. Some users display innate negative responses to new norms and habits related to security, expressing fear about implementing MFA and resistance to changing established routines.
Successful MFA implementation requires organizations to identify and address these specific user concerns through targeted strategies that demonstrate value while reducing friction. Making user training a priority and explaining the new authentication process clearly before rollout begins establishes essential foundation for adoption. Organizations should develop comprehensive communication strategies that let users know why MFA is being implemented, what to expect during setup, how to choose a method and enroll, and where to go for help. This communication should be transparent, avoiding jargon, and available through multiple channels including emails, staff meetings, FAQs, and other resources to ensure all employees receive consistent information.
Phased rollout strategies that start with pilot user groups and expand in stages prove more successful than attempting organization-wide deployment simultaneously. A pilot approach allows organizations to start with core user populations such as IT staff, executives, and remote workers who tend to be more technically comfortable and motivated to adopt security controls. This initial phase provides opportunity to test configurations, capture feedback, adjust policies based on real-world experience, and develop refined processes before expanding. Subsequent phases can roll out MFA to individual departments or user roles, giving the organization time to refine processes and build institutional knowledge about common issues and optimal support approaches.
Offering multiple authentication options provides flexibility that accommodates different user preferences and technical capabilities, increasing adoption rates significantly. Some users may prefer authenticator applications on their smartphones, while others might favor hardware tokens or biometric authentication. By providing options rather than mandating a single approach, organizations demonstrate respect for user preferences while maintaining security requirements. Organizations should also provide backup authentication methods in case users lose access to their primary devices, reducing disruption and frustration when authentication factors become unavailable.
Guided enrollment processes that provide step-by-step instructions, video walk-throughs, FAQ documents, and live training or office hours dramatically reduce implementation friction and user frustration. Some organizations conduct “MFA Day” events where teams enroll together with IT support personnel available to assist, converting a potentially frustrating individual process into a collaborative team event. The more support offered upfront during enrollment, the fewer headaches organizations experience later, as users equipped with proper guidance and support prove far more likely to use MFA correctly and maintain enrollment over time.
Clear and accessible user support must be available to address issues like device loss, forgotten authentication methods, and troubleshooting problems with MFA setup or usage. Organizations should establish helpdesk processes and provide IT staff with training to handle common MFA-related issues efficiently. When users encounter problems and receive prompt, helpful resolution, they develop confidence in the MFA system and are more likely to maintain compliance rather than seeking workarounds. Providing user education about why MFA matters helps transform perception from “annoying security requirement” to “important protection I value.” Sharing real-world examples of how MFA has prevented security breaches, explaining the financial and operational risks that MFA helps mitigate, and demonstrating the minimal actual burden of using modern MFA methods helps shift user perspective.
Securing organizational leadership support proves essential for successful MFA implementation, as employee resistance proves significantly higher when executives do not champion the initiative. When company leadership visibly supports MFA implementation, allocates resources adequately, and demonstrates commitment to security principles, employee adoption follows more readily. Conversely, when implementation proceeds without executive sponsorship, employees encounter an uphill battle with limited resources and perceived organizational ambivalence about security priorities. IT leaders should work to secure C-suite support before beginning MFA implementation, explaining the business case, regulatory requirements, cyber insurance implications, and risk mitigation benefits that MFA provides.
Recent and Emerging Threats Targeting VPN Infrastructure
The threat landscape for VPN infrastructure has intensified dramatically in 2025, with state-sponsored actors, initial access brokers, and ransomware groups demonstrating unprecedented sophistication and coordination in targeting VPN systems for network entry. Recent vulnerability disclosures reveal structural weaknesses in major VPN and firewall products that are being actively exploited in the wild, often for extended periods before vendor discovery or public disclosure. On September 25, 2025, Cisco released a security advisory to patch three security flaws impacting the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) and Cisco Secure Firewall Threat Defense (FTD) software, tracked as CVE-2025-20333, CVE-2025-20362, and CVE-2025-20363. These three vulnerabilities have been actively exploited in the wild by a sophisticated state-sponsored campaign attributed to UAT4356/Storm-1849 (linked to China-based threat actors), representing a significant evolution of the ArcaneDoor attack methodology.
The attack campaign has been actively exploiting these critical zero-day vulnerabilities since May 2025, indicating several months of undetected compromise within victim organizations. Of the three vulnerabilities, CVE-2025-20363 and CVE-2025-20362 do not require authentication, while CVE-2025-20333 requires authentication, but all three vulnerabilities operate over HTTP(S), targeting the web services running on vulnerable devices. The attack leverages a URL path-normalization flaw that can bypass session verification for protected Clientless SSL VPN (WebVPN) endpoints, as well as a heap buffer overflow in the WebVPN file-upload handler, which can result in information disclosure. Threat actors have employed advanced evasion techniques including disabling logging, intercepting CLI commands, and intentionally crashing devices to prevent diagnostic analysis, demonstrating sophisticated operational security practices to evade detection.
The attackers have been observed delivering sophisticated malware families specifically designed for persistence and stealth. RayInitiator is an advanced bootkit targeting Cisco ASA 5500-X devices, providing attackers with persistence through GRUB bootloader modifications and direct manipulation of core system binaries. LINE VIPER is a modular payload system enabling attackers to execute commands, capture network traffic, bypass authentication, suppress logs, and clear traces using encrypted communication via WebVPN sessions and ICMP channels, with anti-forensic capabilities such as forced reboots during core dumps. The campaign reflects highly coordinated, well-resourced threat actors with deep technical knowledge of networking equipment and persistence mechanisms.
The broader trend of targeting VPN and firewall infrastructure reflects a strategic shift by attackers away from consumer targets. Attackers know that compromising a VPN gateway can open the door to entire networks, making these devices high-value targets worth sophisticated exploitation efforts. SonicWall’s recent series of issues highlights the escalating risk, with vulnerabilities giving attackers unfettered access even in environments with multi-factor authentication implemented. Once VPNs were compromised, attackers could pivot laterally, disable defenses, and deploy ransomware at scale. And SonicWall is not alone; Ivanti Connect Secure was hit in early 2024 with multiple zero-day vulnerabilities that gave attackers unfettered access, Fortinet’s SSL-VPN has been the subject of repeated critical flaws including CVE-2023-27997 allowing remote code execution, and Palo Alto’s GlobalProtect was patched in 2024 after researchers uncovered a privilege escalation bug.
The message is clear: VPNs, no matter the vendor, have become one of the most reliable targets for initial access brokers and ransomware groups. The concentration of attack efforts reflects both the criticality of VPN infrastructure to network access and the relative limited number of VPN products dominating the market, meaning that discovery of a single vulnerability can potentially impact thousands of organizations. The global VPN market was valued at $48.7 billion in 2023 and is forecast to hit nearly $150 billion by 2030, growing at a 17.4% compound annual growth rate. This expanding market continues to attract attacker interest as more organizations deploy VPN infrastructure, and defenders struggle to maintain security across a growing attack surface.
Beyond zero-day exploits, attackers continue to exploit known vulnerabilities in VPN systems, demonstrating that patch management failures remain a significant risk factor. Organizations using MySonicWall cloud configuration backup service experienced exposure of firewall configuration backup files containing sensitive information. These configuration files store critical information such as user, group, and domain settings, DNS and log settings, and certificates that enable threat actors to understand network architecture and identify high-value targets. The incident highlights a secondary attack surface beyond the VPN application itself: backup systems, management interfaces, and configuration storage often contain privileged information enabling further network compromise.
Best Practices for VPN MFA Implementation
Organizations undertaking VPN MFA implementation should adopt a comprehensive framework of best practices that address technical architecture, user experience, security policy, and ongoing operations. Regularly updating VPN software and components is fundamental to maintaining secure VPN infrastructure, as patch management is crucial for mitigating vulnerabilities and defending against emerging threats. Organizations must establish procedures for regularly updating VPN client software, servers, gateways, and routers with the latest security patches and firmware, while also establishing emergency patching procedures to promptly address critical vulnerabilities.
Implementing access control and least privilege principles ensures that users have access only to the resources necessary for their job functions, reducing the impact of potential insider threats or compromised credentials. Granular access control policies should restrict VPN access based on user roles, groups, or individual permissions. Organizations should regularly monitor and audit VPN traffic to detect suspicious activities, anomalies, or potential security incidents. Enabling logging and monitoring of VPN traffic allows detection of unauthorized access attempts, unusual patterns, or compliance deviations. Regular security audits and log reviews help maintain visibility into VPN usage and ensure prompt response to security incidents.
Making MFA phishing-resistant represents the highest standard of authentication security for VPN access. VPN security is vastly improved by using phishing-resistant MFA and passwordless authentication methods that completely remove shared secrets, making it impossible for attackers to guess or steal authentication factors. Passwordless authentication based on FIDO standards provides robust defense against phishing, man-in-the-middle (MitM) attacks and hacking attempts by eliminating insecure methods like SMS or OTPs. Since it is based on public-key cryptography, it ensures there are no server-side shared secrets vulnerable to theft in case of a breach.
Thoroughly testing VPN MFA solutions on multiple devices and platforms before full organizational deployment prevents common pitfalls and ensures optimal configuration. Testing should include validation across different operating systems, device types, and network conditions that users will encounter. Optimizing network infrastructure to accommodate increased authentication traffic ensures that MFA implementation does not degrade VPN performance or user experience. Providing backup authentication methods prevents user lockout when primary authentication devices become unavailable, balancing security with operational resilience.
Maintaining and monitoring the system regularly identifies vulnerabilities through regular security audits and detects unusual patterns through authentication log review. MFA software and systems should be kept up-to-date with the latest security patches to address discovered vulnerabilities. Providing clear user support addresses issues like device loss promptly and reduces friction that might encourage users to circumvent security controls. Organizations should review and update MFA policies regularly to align with advancing security needs and threats. Gathering user feedback improves authentication experiences by identifying pain points and opportunities for optimization. Periodically testing effectiveness against emerging threats, including simulated attacks and phishing attempts, validates that MFA implementation achieves intended security objectives.
The Bottom Line: MFA on VPN is Non-Negotiable
The convergence of escalating threats, regulatory mandates, cyber insurance requirements, and technological capabilities creates an unmistakable imperative for organizations to implement multi-factor authentication on VPN accounts without further delay. The evidence supporting this conclusion is overwhelming and multifaceted. Recent data demonstrates that 56 percent of companies experienced VPN-exploited breaches in 2025, yet approximately one-third of VPN users still lack MFA protection, representing a dangerous gap between recognized risks and actual security practices. Research shows that MFA can prevent 99.2 percent of account compromise attacks, 62 percent of breaches could have been prevented with MFA, and 99.99% of MFA-enabled accounts remained secure against attack attempts.
The threat landscape has fundamentally shifted, with sophisticated state-sponsored actors, well-resourced ransomware groups, and organized initial access brokers targeting VPN infrastructure with unprecedented coordination and technical sophistication. Multiple critical zero-day vulnerabilities in major VPN and firewall products have been actively exploited in the wild for months before vendor discovery, demonstrating that product vulnerabilities alone do not account for the scope of VPN-based breaches. Even when technical defenses are properly implemented, authentication weaknesses remain the most reliable attack vector for gaining network access. A single set of compromised VPN credentials can trigger catastrophic compromise including data exfiltration, ransomware deployment, and operational disruption, yet this vulnerability is entirely preventable through MFA implementation.
Regulatory frameworks and cyber insurance requirements have eliminated any remaining ambiguity about the optionality of MFA implementation. HIPAA, PCI-DSS, GDPR, CMMC, NIST standards, and government executive orders all now require or strongly recommend MFA for remote access. Cyber insurance carriers treat MFA as a binary requirement for coverage qualification, with many declining policies entirely for organizations lacking MFA, indicating they have deemed the risk uninsurable at standard rates. This creates powerful business, legal, and financial incentives aligning with security best practices to drive MFA implementation.
For organizations that have not yet implemented MFA on VPN accounts, immediate action is essential. Initial steps should include conducting a comprehensive inventory of all VPN access points, remote access applications, and privileged accounts requiring authentication. A thorough risk assessment should identify which systems and user populations face the greatest threat exposure, using this information to prioritize MFA deployment to the highest-risk areas first. Organizations should evaluate MFA solutions based on security effectiveness, user experience, integration requirements, and cost considerations, with preference for phishing-resistant FIDO-based approaches where feasible. A pilot deployment with a small group of users should precede organization-wide rollout, allowing refinement of technical implementation and support processes based on real-world experience.
Change management and user communications should emphasize the business value of MFA, explaining how it protects organizational assets, enables regulatory compliance, reduces cyber insurance costs, and allows the organization to safely enable remote work. Organizations should implement phased rollout approaches starting with IT staff and executives, then expanding to user populations in stages. Multiple authentication method options should be provided to accommodate user preferences and technical capabilities, with particular emphasis on support for backup authentication methods. Comprehensive user training and readily available support are essential for adoption success.
For organizations that have already implemented some form of MFA on VPN accounts, periodic review and enhancement of existing implementations should assess whether current approaches are phishing-resistant or reliant on weaker methods like SMS that offer lower security guarantees. As employees gain familiarity with MFA, organizations should consider migrating from less-secure methods like SMS or TOTP toward FIDO-based or other phishing-resistant approaches. Continuous monitoring should track MFA effectiveness against emerging threats and identify optimization opportunities. Organizations should maintain current patches and updates on all MFA infrastructure, monitor authentication logs for suspicious patterns, and regularly exercise incident response procedures to ensure rapid response capability if compromise is detected.
The path forward requires sustained commitment to continuous security improvement rather than a one-time implementation followed by complacency. MFA represents essential foundational protection for remote access, but optimal security postures integrate MFA with broader zero trust principles, device health assessment, network segmentation, threat detection and response capabilities, and strong access control policies. By implementing MFA for VPN access while simultaneously advancing toward zero trust architecture, organizations dramatically improve their ability to detect and prevent sophisticated attacks targeting network perimeter access points.
The choice facing organizational leaders is no longer whether to implement MFA on VPN accounts, but rather how quickly to implement it and how comprehensively to extend MFA protection across all remote access vectors and privileged accounts. The security imperative, regulatory mandate, cyber insurance requirement, and financial case for MFA implementation align to create overwhelming justification for immediate action. Organizations that continue operating VPNs with single-factor authentication accept unquantifiable risk in an environment where threat actors have made VPN infrastructure their primary attack target, vulnerabilities are discovered and exploited at accelerating rates, and a single compromised credential can trigger network-wide catastrophe. In contrast, organizations that prioritize MFA implementation for VPN access immediately improve their security posture against the threat landscape of 2025 and beyond.
Protect Your Digital Life with Activate Security
Get 14 powerful security tools in one comprehensive suite. VPN, antivirus, password manager, dark web monitoring, and more.
Get Protected Now
