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The short answer? Maybe. Here’s some things you shouldn’t sneeze at when pondering mainframes and viruses.

Going viral on your mainframe?
Despite the mainframe’s reputation for security and its seemingly impenetrable nature, companies should not naively pass on protecting their systems from viruses. There have been no high-profile reports of mainframes becoming infected or vulnerable to viruses, but there is nothing in the hardware or software architecture that leads to the conclusion that no virus could ever devastate a system’s operations.

Vigilance must remain a priority, especially in systems that are storing customer credit card information or other sensitive data. Companies must remain alert, both in keeping their sensitive data from being stolen or unlawfully accessed, as well as protecting it from being harvested and retrieved by malicious code.
It is unlikely that you would install antivirus software directly on the mainframe, but it should be considered for all of the virtual machines running within the system. Viruses designed to infect Windows and Linux systems are a risk for mainframes running those platforms in virtual environments, making antivirus protection especially important in that context.

Most viruses are spread through email or software downloads (either deliberate or accidental). Mainframes processing high volumes of email or other notes and files must be able to combat the threats of being infiltrated and infected by computer viruses. Protecting the incoming mail servers is a critical first stage in the defense of your system. When emails with piggybacking viruses are blocked before entering into the system, the chance of the system becoming infected is greatly reduced. Removing malicious code, even from compressed or encrypted files, will make the system more secure.

And of course, if you are interested in protecting your sensitive data from the start, strong RACF protection can keep most unwanted visitors out of your mainframe.


Desktop PCs typically are only at risk from their primary user, but mainframes potentially have hundreds or thousands of users interacting with them each day. This would suggest many more potential entry points for viruses. However, despite this difference, individual PCs are still more vulnerable to viruses and malicious code. On mainframes, only experienced administrators generally install new software and update code. In the PC space, both experienced and novice users download and install applications, some of which then infect the computers with malicious code.

Many users operate their PCs with administrative privileges, which let them install viruses and malware that can affect the entire system. On the other hand, mainframes are able to corral data within them so that a problem within one part of the system will not interfere with applications running in other parts. Viruses that could easily spread from one PC throughout the corporate network are rendered sterile within a mainframe environment.

Mainframes are effectively walled off, and there are protocols most companies go through to add new applications and systems. This too makes it far less likely that a virus or Trojan horse program could make its way into the system. This means installing new programs on a mainframe can be a bureaucratic nightmare, but it also ensures the mainframe is well protected from harmful code.

Because of the high stakes type of data mainframes typically process, there is no room for complacency when it comes to protecting these systems from viruses or other malicious code. Every computer system is vulnerable to some degree. However, much can be done to thwart the effects of viruses and to keep them from having any impact on a system’s productivity. You haven’t imagined everything a hacker could come up with, and although there hasn’t been any widely publicized incident or case of a mainframe falling victim to a virus, there is no logical reason to conclude that it will never happen.

So, what’s the upshot? In the end, it’s ultimately a very simple concept: Protecting your system with strong cryptography for mainframe and data, and effective access management, will go a long way in safeguarding your system from external threats.

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