Privacy Watch: Who's Your Software Talking To?

Delving into the sources of a PC's heartbeats.

Andrew Brandt

Andrew Brandt is a senior associate editor for PC World. You can send him e-mail at privacywatch@pcworld.com. To read previously published Privacy Watch columns, click here.

My PC's software is as chatty as a teenager armed with a cell phone--and yours probably is, too.

I'm referring to applications that send short data bursts, called heartbeats, to their company's servers. Heartbeats can enable software updates, help troubleshoot problems, and locate compatible apps on other PCs. But they can also leak--to people who have no business knowing it--information about your PC, your network, and what you do on your computer.

Most software that makes a network connection sends heartbeats: IM programs let the network know you're online; Windows XP goes online to reset your PC's clock; and both Windows and Adobe's Acrobat Reader check periodically for updates or patches. But spyware, adware, and Trojan horse malware that can turn a PC into a botnet zombie send heartbeats, too.

Users rarely know when an app sends a heartbeat. Firewalls can block heartbeats, but this can cause problems if you want to use the app. And once you allow a program to connect to the Net, you may not be able to tell what it does when it reconnects.

I first noticed heartbeats on my PC while running a diagnostic tool's packet sniffer--software that monitors all communication with the outside world. I was trying to detect a specific kind of data transfer, and the heartbeats were an infuriating distraction.

Even when I wasn't using the Net, the diagnostic tool recorded one connection an hour to a Web server at a URL that looked like a jumble of random letters and numbers. As in Edgar Allan Poe's story "The Tell-Tale Heart," the thumping was driving me nuts--especially since, unlike Poe's narrator, I didn't know its cause.

It turns out that the heartbeat's source was my firewall, Zone Labs' ZoneAlarm Pro 6, checking for updates and new antivirus and antispyware definition files. A feature called DefenseNet also sends Zone Labs encrypted info on apps you run and whether you let them connect to the Net.

But before I identified it, I feared that the heartbeat's source might be a keystroke logger sending my passwords to a hacker, or spyware informing an advertising company about my Web surfing habits. I just wanted to turn off the heartbeat as quickly as I could. (To disable the DefenseNet heartbeat, clear the check box labeled Share my security settings anonymously with Zone Labs on the Preferences tab of ZoneAlarm's Overview section.)

I recently tried out Lojack for Laptops, software that uses heartbeats to help a security center track down a notebook if it is stolen. Some might accept the privacy-for-security trade-off, but Lojack's constant tracking made me feel as though my notebook were under house arrest, with a big radio tag around its ankle. Heartbeats can serve useful functions, but sometimes I wish my software would remain silent.

--Andrew Brandt