Technological old timers—that is to say, those of us who were computing before the advent of the Internet—remember when getting your system infected by malicious software, or "malware," was actually relatively difficult.

As organizations rely on documents and e-mail to store mission-critical information, that data will require a higher level of protection. However, groupware environments such as Microsoft Exchange or Lotus Notes — which facilitate the storage and sharing of this data — can spread viruses rapidly when left unprotected.

The cost of cleaning a virus infection at the network server level can be staggering. Infected server files raise the ante on virus infections, rapidly expanding a desktop infection into a network-wide virus outbreak. Although malware infections are relatively infrequent, they can seriously damage your network. Even worse, getting rid of them can take days, resulting in costly downtime and the temporary loss of an essential corporate application.

In essence, three kinds of malware can infect your network through a groupware application: (1) traditional boot-sector viruses hiding in executable programs attached to either e-mail messages or shared documents; (2) macro-viruses activated by opening a shared document file or spreadsheet; or (3) destructive logic bombs.

Computer viruses that attack IBM PCs and compatibles are nearing a milestone of sorts. Within the next few months, the list of viruses will top 1,000, according to Klaus Brunnstein, a noted German computer virus expert. He has published a list of known malicious software for MS-DOS systems that includes 979 viruses and 19 trojans. In all, there are 998 pieces of "malware," Brunnstein said.