The Hidden Vulnerability: Why Your IBM i Systems Need Modern Security Controls

The Security Model That Used to Work 

Every IT director who manages IBM i infrastructure knows the platform’s reputation: rock-solid reliability, decades of uptime, and a security track record that made it the trusted backbone for mission-critical applications. For years, the security posture was straightforward and effective. IBM i systems weren’t directly connected to the internet. They ran proprietary applications in isolated environments. Physical separation provided real protection. 

This wasn’t a misconception. It was legitimate security for its time. 

The challenge is that the environment evolved while our assumptions stayed frozen in that earlier era. Organizations added file sharing capabilities so Windows users could access IBM i data. They integrated APIs to connect modern applications. They built hybrid infrastructures where IBM i became a network citizen rather than an isolated island. The mental model of “not on the internet equals secure” persisted even as the actual infrastructure changed fundamentally. 

Today, IT teams managing these systems often carry security knowledge configured 20 to 30 years ago, based on paradigms that genuinely worked then but don’t address how these systems operate now. The result is a dangerous gap between perceived security and actual vulnerability. 

The Bridge No One’s Watching 

The transformation happened quietly. When IBM i takes on the role of file server using NetServer and SMB/CIFS protocols, it creates a network bridge to Windows environments. This is where the security model breaks down in ways most organizations haven’t fully recognized. 

To ransomware moving laterally through a network, IBM i file shares look identical to any other mapped drive. The malware doesn’t need to understand RPG or navigate the object-based architecture. It simply sees network storage and does what it’s designed to do: encrypt everything it can access. 

The evidence shows up every week. Security incidents that compromise customer environments are no longer occasional events but regular occurrences. The pattern repeats: an attacker gains entry through a softer target (a Windows endpoint), exploits missing multi-factor authentication or compromised credentials, then moves laterally through the network using the trusted file sharing infrastructure that organizations assume is protected by IBM i’s inherent security. 

The statistics paint a stark picture. Ransomware attacks have increased 13% over the past five years globally, with incidents now occurring every few seconds. More concerning for organizations running IBM i as file servers: these attacks don’t require sophisticated knowledge of the platform. They just need access to the file shares. 

The Attack Path in Plain Language 

Understanding how these compromises actually happen helps cut through the complexity. The attack follows a predictable three-stage progression. 

Stage one begins with the softer entry points. An employee clicks a phishing link, or credentials get harvested through a brute-force attack on an account without multi-factor authentication. Sometimes it’s a forgotten administrative account that nobody remembered to disable. The attacker now has a foothold on a Windows endpoint somewhere in your network. 

Stage two is lateral movement. The compromised endpoint has mapped drives pointing to IBM i NetServer shares. These file shares use the same SMB protocol as any Windows file server. The attacker doesn’t see a difference. They navigate through the available shares, looking for valuable data or simply spreading their payload as widely as possible through the network. 

Stage three is when the damage becomes visible. Ransomware executes and begins encrypting files. Because IBM i’s Integrated File System can contain PDFs, Word documents, Excel files, and any other file type, these become targets just like files on a Windows server. If the file shares include write access to root-level directories, the encryption can spread across the entire IFS. 

Then comes the phone call nobody wants. Your operations are down. Critical files are encrypted. You’re facing a binary choice: pay the ransom or restore from backup. 

The financial impact extends far beyond the ransom itself. The average ransomware attack in 2024 cost organizations $5.13 million, and that figure is projected to reach $5.5 to 6 million in 2025. Organizations typically face 21 to 24 days of downtime during recovery. The harsh reality: only 46% of victims who pay the ransom successfully recover their data, and that data is often corrupted. Perhaps most troubling, 80% of organizations that pay a ransom experience another attack. 

Recovery costs typically run 50 times higher than the ransom payment itself. This includes the value of lost business during downtime, the cost of forensic investigation, the expense of full environment restoration, regulatory penalties in industries like healthcare and financial services, and the long-term impact on brand reputation. In one survey, 53% of ransomware victims reported brand damage following an attack. 

Even with solid backup practices, you lose everything created since the last backup. For organizations running just-in-time operations or processing high-volume transactions, that data loss alone can be devastating. 

What Modern IBM i Security Actually Looks Like 

The good news is that securing IBM i in hybrid environments is entirely achievable. It requires updating both the technical controls and the operational mindset to match how these systems actually function today. 

Modern security starts with visibility. Comprehensive audit logging should capture all file server access, privileged operations, and system changes. This logging data needs to flow into a centralized SIEM system where security teams can actually monitor it, correlate events, and respond to anomalies. IBM i has built-in intrusion detection capabilities that monitor TCP/IP network activity for potential attacks, but these need to be enabled and actively monitored. 

Antivirus scanning on the Integrated File System is no longer optional. Both scan-on-open and scan-on-close options exist but remain underutilized in most deployments. Since the IFS can contain any file type that might carry malware, treating it with the same security discipline as Windows file servers is essential. 

Multi-factor authentication should protect every access point to IBM i, especially for file server access and administrative functions. This single control eliminates the most common entry vector for credential-based attacks. 

Configuration fundamentals matter enormously. The single most critical rule: never share root-level directories, especially not with write access. There is simply no legitimate operational reason to expose your entire file system through a network share. When file shares are necessary, make them as narrowly scoped as possible and set them to read-only wherever feasible. 

System security levels should be set to at least 40, with 50 being even better. However, system-wide settings alone don’t provide sufficient protection. Object-level authority controls are essential because simply restricting menu access only controls what’s visible on screen, not what users can actually accomplish through the command line or other interfaces. 

Default configurations are particularly dangerous. Many IBM i systems still have usernames and passwords configured to match, or they use other default credentials that are trivial to compromise. Strong password policies, regular cleanup of inactive user profiles, and encrypted data transmission using SSL for services like FTP and Telnet are all fundamental requirements. 

Exit point programs provide crucial monitoring for external access through file servers and other services. IBM provides the exit points but doesn’t supply the programs themselves. Third-party solutions that implement proper exit point monitoring are necessary to capture the audit trail most organizations need. 

Perhaps most importantly, this isn’t a set-it-and-forget-it exercise. Security configurations need regular assessment. IBM recommends annual security assessments for IBM i environments to identify misconfigurations, validate that controls match current threats, and adapt to the evolving risk landscape. 

The Conversation You Need to Have 

If you manage IBM i infrastructure or make decisions about its security, there are specific questions worth asking this week: 

When was our last comprehensive IBM i security assessment?  

• If the answer is “never” or “not in the past two years,” that’s a red flag. 

Do we have root-level file shares configured?  

• If yes, what’s the business justification, and can we eliminate or restrict them? 

Are our file shares set to read-only wherever possible?  

• Every file share with write access is a potential encryption target. . 

Is our IBM i audit logging forwarded to a SIEM where security teams actually monitor it?

• Logging that nobody reviews provides no security value

Do we have multi-factor authentication enabled on all access points to IBM i, including file server access? 

• If not, you have a significant vulnerability. 

Do we have antivirus scanning enabled on the IFS?  

• Many organizations still operate under the outdated assumption that IBM i doesn’t need malware protection. 

Who on our team has current expertise in IBM i security, not just IBM i administration?  

• The skillsets are different, and the knowledge required has evolved significantly. 

These aren’t theoretical questions. They identify concrete vulnerabilities that attackers are actively exploiting. The organizations calling for incident response help every week often discover they’ve been operating with security assumptions that haven’t been validated in years or even decades. 

The reality is that security assumptions are expensive when they turn out to be wrong. A systematic assessment identifies specific vulnerabilities in your configuration, validates whether your current protections actually match the threats you face, and provides a clear roadmap for closing gaps before they become incidents. 

Your IBM i infrastructure likely runs applications that are genuinely mission-critical to your business. The reliability and stability that made these systems valuable for decades remains intact. What needs to change is ensuring that the security posture matches how these systems operate in today’s integrated, networked environments. 

The organizations that are getting this right aren’t necessarily spending dramatically more on security. They’re spending strategically on the controls that address their actual risk, and they’re validating their assumptions rather than relying on outdated mental models. 

Ready to validate your IBM i security posture? Schedule a call with our infrastructure team. We’ll walk you through the specific considerations for securing IBM i in hybrid environments and help you identify where your current configuration might have gaps. Schedule Your Security Assessment Call 

About CloudSAFE 

CloudSAFE delivers purpose-built cloud infrastructure and disaster recovery solutions for mid-market organizations running IBM i systems and modern Windows/Linux servers. Our expert-driven approach combines deep technical knowledge of IBM i environments with comprehensive security assessments designed to protect mission-critical operations in today’s hybrid infrastructure landscape. 

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