What Is a Virtual Private Network (VPN?)
A Virtual Private Network (VPN) is a technology that creates an encrypted connection between a user’s device and a remote network or service.
This encrypted connection protects data as it travels across public networks, allowing users to access internal systems and applications as if they were directly connected to a private network.
What Are VPNs Used For?
VPNs are commonly used to support:
- remote work
- connect branch offices
- secure communications over untrusted or public networks, like (like a coffee shop or a hotel’s Wi-Fi)
By encrypting traffic and authenticating users, VPNs help prevent data interception and tampering, as well as casual eavesdropping. However, encryption alone doesn’t determine whether a connection is trustworthy or safe.
In modern environments, VPNs function primarily as access mechanisms, not security guarantees. They enable connectivity, but they can’t validate intent, continuously assess risk, or detect compromise without additional security operations and monitoring.
Why VPNs Became Essential for Remote Access
VPN adoption accelerated as organizations moved beyond centralized offices and began supporting remote employees, third-party partners, hybrid environments, and geographically distributed infrastructure.
Early VPN deployments focused on connecting branch offices and traveling employees to corporate data centers without the cost of dedicated private circuits. As remote work expanded during the pandemic, VPNs became a default solution for granting users access to internal applications, file shares, and administrative systems. Cloud adoption also sped VPN adoption, with organizations relying on VPN tunnels to connect on-premises environments to cloud workloads and service providers.
Why Are VPNs So Popular?
Today, VPNs remain widely used because they are:
- ramiliar
- broadly supported
- relatively easy to implement
At the same time, however, their role has shifted. VPNs no longer sit at the edge of a clearly defined perimeter. Instead, they often serve as one of many entry points into complex hybrid environments.
This shift has exposed a fundamental tension: VPNs were designed to provide secure connectivity, but threat actors are finding novel ways to use them as high-value targets for initial access.
How Does VPN Technology Work?
When a user initiates a VPN connection, their device establishes an encrypted session with a VPN gateway using protocols such as IPsec or SSL/TLS. This process creates a virtual network interface that routes selected traffic through the encrypted tunnel.
This encryption protects data confidentiality by transforming readable information into ciphertext that can only be decrypted by the VPN endpoint. Modern VPNs typically use strong cryptographic algorithms and support features such as perfect forward secrecy, which limits the impact of credential compromise by generating unique session keys.
Authentication determines whether a user is allowed to connect. Historically, VPNs relied on single-factor authentication — like usernames and passwords — which proved vulnerable to phishing, credential reuse, and brute-force attacks. Many organizations now implement multi-factor authentication (MFA) to strengthen identity verification.
MFA combines multiple authentication factors from different categories: something you know (like a password or PIN), something you have (such as a smartphone or security key), and something you are (including biometric markers like fingerprints or facial recognition).
However, not all MFA methods provide equal protection, and threat actors are constantly refining techniques to evade or bypass MFA.
Once authenticated, the VPN gateway decrypts traffic and forwards it into the internal network. From the perspective of internal systems, VPN-connected users often appear similar to on-site users. This architectural characteristic simplifies access but also creates risk if access controls are overly broad.
What Are Common VPN Deployment Models?
Organizations use VPNs in several common configurations, each with distinct risk considerations:
Remote Access VPNs
Remote Access VPNs allow individual users to connect to internal resources from external locations. These deployments are widely used for remote employees and contractors but are frequently targeted by attackers seeking stolen credentials or exposed authentication interfaces.
Site-to-Site VPNs
Site-to-site VPNs connect entire networks, such as branch offices or cloud environments, through persistent encrypted tunnels. While effective for connectivity, they can extend trust across environments if segmentation is not carefully enforced.
Cloud-Hosted VPNs
Cloud-hosted VPNs services provide scalability and ease of deployment, particularly for distributed workforces. However, they remain subject to the same credential, configuration, and monitoring challenges as traditional VPN infrastructure.
Regardless of the deployment model, VPNs centralize access in ways that make them attractive to threat actors.
The Security Risks Inherent in VPN Infrastructure
VPNs introduce several well-documented security challenges that organizations must actively manage. According to the Arctic Wolf 2026 Predictions and Threat Intelligence Report, compromised VPN credentials and other forms of external remote access were the cause of nearly two-thirds of non-BEC incident response cases investigated by Arctic Wolf — a surge of 41% in just two years.
Credential Compromise
Credential compromise represents the most common form of VPN failure. Threat actors obtain valid credentials through phishing campaigns, malware, or underground marketplaces, then use them to successfully authenticate, with their activity often blending into normal VPN traffic.
Vulnerability exploitation presents another major risk. Internet-facing VPN gateways are routinely scanned for known vulnerabilities. Organizations that delay patching due to availability concerns inadvertently provide attackers with reliable entry points.
Configuration weaknesses further compound these risks. Overly permissive access rules, lack of network segmentation, weak encryption settings, or insufficient logging can allow threat actors to move laterally once they’ve gained access. In many environments, a single VPN account can provide broad access to internal systems.
Encryption itself can also create visibility gaps. While VPN encryption protects data in transit, it can also obscure malicious activity from security tools that lack the ability to correlate authentication events with endpoint, identity, and network behavior.
VPNs and the Limits of Trust
A core limitation of VPNs is that they establish session-based trust. Once a user authenticates, access is often granted broadly for the duration of the session. This overly permissive model assumes that authentication equals trust, an assumption that modern attackers routinely exploit.
Zero trust security principles challenge this assumption by treating every access request as inherently risky, regardless of network location. In zero trust models, authentication access decisions incorporate device health, behavior, context, and continuous verification.
VPNs can coexist with zero trust strategies, but only when paired with strict access controls, segmentation, and ongoing monitoring. Without these safeguards, VPNs can amplify risk by providing attackers with persistent, trusted access paths.
What Are Best Practices for Reducing VPN Risk?
Reducing VPN-related risk requires more than deploying stronger encryption. Organizations must combine technical controls with operational oversight.
Strong Authentication is Essential.
Phishing-resistant MFA significantly reduces the likelihood of credential-based compromise. Additionally, access should be limited to only the systems and services required for each role.
Network Segmentation
Network segmentation limits lateral movement by restricting what VPN-connected users can reach.
Logging and Monitoring
Logging and monitoring of VPN activity provides visibility into authentication attempts, session behavior, and anomalous access patterns.
Regular Assessments
Regular assessment are key to helping identify exposed services, outdated software, and misconfigurations before attackers exploit them.
These practices assume that compromise is possible and focus on detection and containment rather than prevention alone.
What is An Example of a Real-World VPN Credential Compromise?
Consider an organization that relies on a VPN to support a fully remote workforce. An employee unknowingly submits credentials to a phishing site. The attacker uses those credentials to authenticate through the VPN during normal business hours.
From the VPN’s perspective, the connection appears legitimate. The attacker accesses internal systems, explores network shares, and establishes persistence. Without correlated visibility into endpoint behavior and identity anomalies, the activity remains undetected until significant damage occurs.
This scenario illustrates why VPNs alone cannot defend against modern intrusion techniques.
How Arctic Wolf Helps
The Arctic Wolf Aurora™ Platform ingests and correlates telemetry from VPN gateways, identity systems, endpoints, and network controls to identify anomalous authentication patterns and post-authentication abuse. According to the Arctic Wolf 2025 Security Operations Report, the platform analyzes tens of billions of observations per customer annually, enabling early detection of subtle, credential-based attacks.
Arctic Wolf® Managed Detection and Response provides 24×7 monitoring and analyst-led investigation of VPN-related activity, helping organizations detect compromised accounts before attackers escalate.
