Somewhere Over the Spreadsheet

Two years ago I was standing in front of a group of security geeks in Santa Barbara for BSides LA talking about the sophisticated tools that most network engineers use — like “ping” and “traceroute” and even Excel — and about how the broad range of tools available typically didn’t get used in a primordial jungle of our enterprise networks. Recently, Wired concurred, outlining the widespread use of spreadsheets for a broad range of business functions.

new-spreadsheet1It is embarrassingly common for us to find the majority of network management information in spreadsheets. Lists of devices, lists of firewall rules, hierarchies of networks. All laid out in nicely formatted tabs within multiple spreadsheet workbooks, often stored in SharePoint or Google Docs. But, always, devoid of context and the real meaning of the elements.

This isn’t to say that there isn’t a place for spreadsheets, of course, but I would challenge you to think through how you are using them and whether or not they are giving you the information you need to know rather than believe what your network is really doing.

For example, a couple years ago I was visiting a major retailer as they were working through their PCI audit. They presented the auditor with an annotated spreadsheet containing all of the firewall rules within their infrastructure. The auditor, for his part, recognized that evaluating firewall rules out of context masks the reality of the way a network operates, and asked to review the PCI zones using RedSeal. The insights for the organization and the auditor were rapid and clear, and the organization was able to take steps to improve their overall security as a result.

So, although spreadsheets are valuable for building lists of the “stuff” that makes up your environment, they are no substitute for automation that can show you and tell you what you don’t know you don’t know. What do you keep in spreadsheets? What do you wish your spreadsheets could tell you? What’s the strangest experience you’ve had with spreadsheets?