As the number of interconnected computers grows within our organizations, the traditional areas of security and high availability (HA) are rapidly overlapping. It used to be that security meant keeping an eye on who had access to the information, while high availability meant controlling the number of interruptions that prevented access to information resources.

Today, with office machines seamlessly connecting to the Internet through myriad network devices and with desktop computers interchanging files with increasing translucence, maintaining the availability of any particular information system also means protecting the networks from viral attacks that can diminish response time.

Where Security and High Availability Overlap

Witness the impact of recent network denial of service (DoS) attacks or the effects of the Blaster.D on Windows servers. The network failure, which destroyed the availability of information systems, was the result of unscheduled events that were borne by agents outside the organization. Preventing such attacks traditionally belongs to the realm of security, yet when security on the network level fails, availability to information resources will fail as well.

In dealing with the topic of HA and the iSeries, such considerations become very important, particularly when investigating the use of the iSeries Integrated File System (IFS).

The iSeries IFS for HA

The IFS is a great resource for helping to establish a system-wide HA profile: It can act as a central file resource that can be readily scheduled for maintenance and service. It's a fast and reliable network resource, so your users can have ready access to their shared data. In addition, the IFS--used in conjunction with the ISX/ISA for Windows Server or with LPAR for UNIX or Linux--keeps the supportable profile of the entire information system very manageable indeed. The IFS seems at first glance to make the iSeries the perfect HA server. It allows users running UNIX, Linux, or Windows operating systems to connect to the iSeries and run executable code from the file system itself. Web pages, Word documents, even executable code can be stored simply and safely on the iSeries to make backup and restore functions much more centralized and efficient. These advantages make the iSeries a great consolidation server and can greatly enhance the availability of the entire information system.

However, the IFS also is one of the iSeries' weakest links. Why? Because of its vulnerability to viruses, worms, and other rogue agents. This has been, traditionally, one of the reasons the IFS has caused many IT administrators to pause.

Is the IFS the Achilles Heel?

Don't get me wrong! OS/400 itself has proven to be immune to most of the virus threats that currently infect computer systems. The system has maintained its immunity by employing a unique program/object security model, wherein all OS/400 entities--files, data areas, programs, etc.--are stamped with an immutable designation that identifies each object, its size, and any attempt to modify it. This security system is embedded in the operating system itself, making it one of the most bulletproof in the industry: Any change in a byte of executable code immediately alerts the operating system with a message, and the "damaged object" is quarantined. The process of repairing the damaged object requires that it be recompiled, a lengthy and involved process that checks out the validity of the object. So secure is this method of protection that, to date, there have been no reports of worms or viruses penetrating the native iSeries file system.

This has led many iSeries customers to believe that their systems are completely protected from virus-instigated downtime. But, in reality, until recently, the iSeries had an Achilles heel: the IFS.

The Problem with Mimicking File Systems

Though OS/400 itself seems relatively immune from malicious agents, the IFS, which acts as a storage receptacle for non-OS/400 code and files, can also act as an unwitting host to many of the same rogue agents that impact other operating systems. In other words, because it mimics the capabilities of UNIX and Microsoft file systems, it also mimics the file-level vulnerabilities that come with those operating systems. It's the translucent qualities of the IFS that allow it to become infected with the same viruses and worms that impact Windows and UNIX systems. Though these rogue agents can't hurt the iSeries itself, they can pass through the iSeries onto client machines or connected servers. This can be a deadly scenario for the entire network of interconnect servers.

A Deadly Scenario

Imagine the havoc should a memory-resident network virus such as W32.PinFi find its way onto an iSeries IFS. The W32.Pinfi virus spreads rapidly along network shares by attaching itself to the Windows Internet Explorer. In the process of replicating itself, it slows down network response to a crawl while it attaches itself to various pieces of Windows executable code and registries. Users who connect to the IFS could very easily infect non-iSeries applications that are stored there. When accessed by other client machines, the virus code segments could reactivate W32.Pinfi's hidden parcel of maliciousness and cause a substantial interruption of service. Under such a circumstance, W32.Pinfi could quickly jump along network shares between machines, infect other servers, and ultimately pull down the network. And since the W32.Pinfi virus resides in the PC's memory, the only means of disabling the code would be to shut down all of the PCs themselves or disconnect them physically from the network. Meanwhile, running anti-virus scanning software might locate the virus on the PC and remove it, but the malicious code that began the infection might still reside on the iSeries IFS. By the time the network administrator figures out the source of the outbreak, availability of the network could be severely compromised.

Tradeoffs for the IFS?

So, on the one hand, the IFS aids the HA effort by centralizing backup and recovery and by allowing the storage of dispersed resources to be centrally accessible. But, on the other hand, the IFS could become a nest of corruption for the entire network.

So what's the solution? How can the IFS be encompassed as an asset of HA while simultaneously protecting its resources from unwitting abuse?

PC Scanning of the IFS

Until recently, the only workaround was to scan the IFS using anti-virus scanning software that was run from a computer that connected across the network itself. Unfortunately, this also meant dedicating an attached PC solely to the purpose of safeguarding the integrity of the IFS--an odd arrangement, considering the iSeries itself needs no such protection.

Scanning the IFS from an attached PC is not a trivial process: When running the PC's anti-virus software, all the data contained within the IFS is transferred byte by byte across the network into the memory of the scanning PC. This process could take hours to perform, incrementally slowing the entire network.

Yet PC scanning of the IFS has been the status quo for anti-virus protection on the IFS until last June when Bytware introduced its StandGuard Anti-virus software product.

New Products for the IFS

StandGuard Anti-virus is a native OS/400 iSeries application that goes after the files that reside on the IFS and heuristically scans all the data and executable code that it finds there. Bytware teamed up with Network Associates (the makers of the McAfee line of anti-virus solutions) to combine the skills necessary to create StandGuard Anti-virus. This is a significant product. It does the following with files on the IFS:

• Detects and cleans macro and script viruses
• Detects and cleans encrypted and polymorphic viruses
• Detects and cleans new viruses in executable files and OLE compound documents
• Detects and removes Trojan horses, worms, and many other types of malicious software
•  Scans within compressed files
• Decompresses and scans files compressed in packages such as PKZip, .LHA, and .ARJ
•  Upgrades easily to new anti-virus technology

Since the introduction of StandGuard Anti-virus, Bytware has also developed an enhancement that scans iSeries email. This enhancement allows the iSeries to scan email before it reaches the PC clients that use the iSeries email services. The enhancement performs the following functions:

• Scans iSeries SMTP email at the server
• Scans inside archive files such as .ZIP, .JAR, etc.
• Detects header exploits and malformed MIME
• Redirects infected or suspicious email to an Administrator

The Need for More IFS Hybrid Software

Right now, Bytware is the only vendor that has native iSeries products to perform these two important security functions. The services are approved by IBM, and the feedback from customers sounds positive. But we hope that, in the near future, there will be more products available that specifically address the unique nature of the iSeries IFS.

In the meantime, consider the IFS one of your strongest assets for HA. But don't forget that--like the file systems it mimics--without protection it can also be a substantial liability for security.

Thomas M. Stockwell is Editor in Chief for MC Press, LP.