Even the recording industry has gotten in on the game. In 2004, a company working for the record companies started seeding file-sharing sites with media files containing a Trojan that downloaded adware and opened multiple pop-up windows on the user’s computer.

Even if the files don’t contain hidden nasties, the files themselves can be problems, with copyright violations and pornography the most obvious example.

8. Unnecessary Modems
A lot of computers, especially older ones, included built-in modems whether or not they were needed. In other cases, servers have modems connected directly to outside lines for purposes of monitoring and maintenance. In either case, unneeded modems provide another path into your network, an unnecessary path that brings with it a host of potential problems.

War dialing isn’t as popular an attack as it once was, but some bad guys still use it, and an unprotected modem attached to your network is just as dangerous as ever.

A lot of these extra modems aren’t covered by the company firewall, and in fact IT may not even realize they exist. In a lot of cases, the user can simply plug the modem into the telephone system and make a direct connection to the Internet—with all the danger that implies. Monitoring and maintenance modems are typically controlled by the vendor supplying the equipment, and you’re relying on that company to make sure the security software is up to date.

While some modems may be necessary, especially for remote maintenance, it’s important to have a complete inventory of all the modems attached to the network and to make sure the ones that are attached are both necessary and properly protected.

9. Unauthorized or Unsecured Synchronization Software
Laptops, PDAs and even phones use synchronization software to keep everything updated, from calendars to contact lists. This is convenient, especially when combined with technologies like Wi-Fi or Bluetooth. However, allowing any device to synchronize can open a serious security hole, especially since many of these programs work in the background and the user may not be aware of what is being uploaded and downloaded. At the very least, this can give access to shared folders and Exchange server.

10. Wireless Connectivity
According to In-Stat and Meta Group, something like 95 percent of all laptop computers now come with built-in wireless access. In spite of the lessons of TJX’s massive loss of customer information, and the resulting dropping stock price and $12 million charge, some enterprises still haven’t secured all their endpoints with wireless connectivity.