You know not to do it. You don’t respond to those emails asking you to update your Social Security number or credit card, bank, and other financial information or verify your password at eBay, PayPal, or other ecommerce Web sites.

You don’t because you know that chances are high that this is a criminal attempt to steal your identity and your money, and you’d then be left spending many tedious hours trying to straighten out the mess afterward.

Among the latest phishing attacks are emails that appear to come from the Internal Revenue Service, trying to trick you into revealing the bank you do business with. The criminals then send an email that appears to come from that bank, asking you to log onto its Web site. But the Web site you’re directed to only looks like your bank’s site. It’s actually a bogus site put up by the criminals to get your account data, so they can log onto your bank’s real site and clean you out.

People still get suckered into these “phishing” scams, with the Anti-Phishing Working Group (www.antiphishing.org) receiving an average of about 25,000 reports of such attacks each month. Many people think of cybercriminals as operating abroad, away from the reaches of American law enforcement, and many do. But the country hosting the greatest number of phishing Web sites is the U.S., according to the group. The average time that these sites stay up is about 4 days—long enough to do their dirty work.

Phishing originated with America Online back in the mid-1990s, with teenage tricksters enticing naive users into revealing their passwords to “verify your account” or “confirm billing information.” It later evolved into a more nefarious mode, involving credit cards and other financial information, but with the same kinds of pitches being used. By 2004 it was a full-scale crisis. It still is.

Other techniques phishers use are addressing victims using their real names; sending email that appears to come from a trusted friend or co-worker; using a Web address for the phishing site that’s very close to that of the real site, featuring images at the phishing site that were stolen from the real site; using links at the phishing site that connect to the real site; and employing scripts at the phishing site that place a picture of the real Web address over the address bar.

Protecting yourself against phishing isn’t difficult, and new software provides extra protection.

Never click on a link in an email message asking you to verify any personal or financial information via the Web. No legitimate company or government agency should ask you to do this. If you think it may be legitimate, phone the company and ask if such an email went out.

Be careful, though, of emails asking you to phone your bank or credit card company to verify information. The phone number may be bogus, directing you to the criminals, who will then try to steal your information. Look up the phone number yourself.

Be wary of any links in email messages. Verify that the Web address the link will take you to is the same address it indicates. Phishers often use the correct Web address as the name of the link, but code the link to take you to the bogus address. Be especially wary of Web addresses that include the @ symbol or email messages that ask you to click on an image.

Be careful when typing Web addresses into your browser so a typo doesn’t land you at a phishing site by mistake. Using a bookmark or favorites link will prevent this.

Use the latest versions of Microsoft Internet Explorer, Mozilla Firefox, or Opera, which all have anti-phishing features. Make sure you enable these features and keep the software up-to-date.

Protect yourself with an Internet security suite such as Norton 360, McAfee Total Protection, or the security software provided by your Internet service provider. Make sure you keep this software up-to-date as well.

Be careful about social networking sites such as MySpace and Facebook, as well as the increasing number of business and professional social networking sites that are popping up. Scammers troll these waters looking for innocents to bait, tricking them into revealing financial information, Social Security numbers, mothers’ maiden names, and so on.

You may be savvy enough to avoid the above mistakes—make sure your family members, friends, and co-workers are as well.