Most breaches don’t start with malware or zero-day exploits. They start with a login. 

An attacker gets hold of a password, maybe through phishing, reuse, or a leaked credential dump. They test it against a remote system. An SSH prompt appears. The credentials work. From there, everything unfolds quietly – privilege escalation, lateral movement, persistence. By the time anyone notices, the damage is already done. 

This is why multi-factor authentication (MFA) matters. And more importantly, it’s why where you enforce MFA matters. VPNs and cloud apps get attention. But the real crown jewels are Linux servers, Unix systems, and network devices. These systems handle sensitive data and traffic and are high exposure. Far too often, they are protected by nothing more than a password or an SSH key. 

Securing Linux, Unix and Other Critical Infrastructure Systems  

Picture a production Linux server running core business workloads. It’s reachable over SSH. Engineers access it every day. Automation jobs connect to it constantly. Somewhere along the way, a password or key leaks. 

Without MFA, that single mistake is enough. The attacker doesn’t need to exploit anything. They simply authenticate as a legitimate user. 

MFA changes that moment entirely. When enforced at the point of remote access, a stolen credential becomes a dead end. The password may be valid, the SSH key may be correct, but without the second factor, access simply stops. 

This is especially critical for infrastructure systems that were never designed with modern identity controls in mind. Linux and Unix servers rely heavily on privileged credentials and SSH. Network devices often depend on local administrative accounts. These systems are powerful, deeply trusted, and broadly connected. 

They are also historically difficult to protect with MFA. That’s because there is limited native support for MFA, architectural complexity, and heavy integration requirements. Add to the challenge, legacy PAM solutions were not built to enforce MFA directly at the SSH or infrastructure access layer.  Solutions often rely on one of three approaches: 

• VPN-level MFA, which protects network access but not the actual privileged session. 

• Agent-based deployments that require software installed on every server. 

• Password vaulting without true session control. 

The result is inconsistent or no MFA protection across these critical systems.  

12Port PAM brings MFA Directly Into Remote Access 

With today’s threat landscape, MFA should not be bolted on after login. It should be built into the remote access workflow itself. 

Modern Privileged Access Management (PAM) solutions are changing that. Using 12Port’s agentless PAM platform, MFA is enforced inside the session brokering process. When a user initiates an SSH connection to a Linux or Unix server — or attempts to access a network device — the connection is intercepted and evaluated before access is granted. 

MFA is required at that exact moment. Only after successful verification does the session proceed. 

With this modern approach, there are: 

• No agents to deploy on servers 

• No changes to how engineers connect 

• No disruption to approved automation 

• No exposure of credentials 

Passwords and SSH keys remain securely vaulted and are never revealed to the user. They are injected into the session only after MFA succeeds. This approach allows organizations to consistently enforce MFA across the systems attackers most frequently target without breaking workflows or rewriting infrastructure. 

In practice, MFA can be applied to: 

• SSH access to Linux and Unix servers 

• Privileged administrative access to infrastructure systems 

• Network devices that lack native MFA support 

• Human users without disrupting automation accounts 

By embedding MFA directly into remote access, 12Port PAM helps organizations remove one of the most common and effective attack paths from their environment. 

Final Thoughts 

When breaches begin with a login, securing remote infrastructure with MFA isn’t just a best practice. It’s the control that turns a stolen password into a failed attempt.  

Learn more about how 12Port PAM enforces MFA directly within privileged remote access — and start a free trial today. 

12Port Documentation Enforce MFA for remote access to Unix servers and Network Devices. 

12Port Blog, How to Enable MFA Before RDP and SSH Sessions  

The post Preventing Breaches – MFA on Remote Access to Linux, Unix, and Infrastructure Systems appeared first on 12Port.

*** This is a Security Bloggers Network syndicated blog from 12Port authored by Peter Senescu. Read the original post at: https://www.12port.com/blog/preventing-breaches-mfa-on-remote-access-to-linux-unix-and-infrastructure-systems/