What is spam email?

How spam works

Why do people send out spam email?

Often, spam email is sent for commercial purposes. While some people view it as unethical, many businesses still use spam. The cost per email is incredibly low, and businesses can send out mass quantities consistently. Spam email can also be a malicious attempt to gain access to your computer.

How do you deploy anti-spam tactics?

Spam email can be difficult to stop, as it can be sent from botnets. Botnets are a network of previously infected computers. As a result, the original spammer can be difficult to trace and stop.

If you receive a message that appears to be spam—for example, if you don’t recognize the sender—mark the message as spam in your email application. Don’t click any links or attached files, including opt-out or unsubscribe links. Spammers sometimes include these links to confirm that your email address is legitimate, or the links may trigger malicious webpages or downloads.

Anti-spam solutions should address a wide range of known threats beyond spam, phishing and botnet attacks that include hard-to-detect short-lived and low volume email threats. See the advanced threat features of Email Threat Defense.

Is spam email dangerous?

Spam email can be dangerous. It can include malicious links that can infect your computer with malware (see What is malware?). Do not click links in spam. Dangerous spam emails often sound urgent, so you feel the need to act. Keep reading to learn about some of the basic spam types.

Common types of spam

Commercial advertisements

Whether an email message is spam or a legitimate advertisement, in the United States it's subject to the guidelines in the CAN-SPAM act.

When businesses capture your email address, they often subscribe you to their newsletter by default, as a low-cost way to sell their products. Whenever you fill out an online form, look for a checkbox to opt into or out of marketing email. While these emails can be pesky, most are harmless, and by law they must have a visible opt-out or unsubscribe option.

If you unsubscribe and continue to receive spam, update your email settings to filter messages from the sender's address out of your inbox.

Antivirus warnings

Ironically, antivirus warnings are a common spam tactic. These emails warn you about a computer virus infection and offer a solution—often an antivirus scan—to fix the alleged cyber threat. But taking the bait and clicking the link can grant the hacker access to your system or may download a malicious file.

If you suspect that your computer is infected, do not click a random email link. Instead, pursue legitimate cybersecurity software solutions to protect your endpoints.

Email spoofing

Why are phishing email scams often effective? Because the spam emails masterfully mimic legitimate corporate messages to get you to act. In a spoofing attack a spammer picks a company brand victims will trust, such as a bank or an employer, then uses the company's exact formatting and logos.

Before you reply or click anything, check the From line to make sure that the sender's email address (not just the alias) is legitimate. When in doubt, contact the company to verify whether the email is real.

Sweepstakes winners

Spammers often send emails claiming that you have won a sweepstakes or a prize. They urge you to respond quickly to collect your prize, and may ask you to click a link or submit some personal information. If you don't recognize the competition, or if the email address seems dubious, don't click any links or reply with any personal details.

Money scams

Unfortunately, spammers prey on people's goodwill. A common money scam begins with emails asking for help in dire circumstances. The spammer fabricates a story about needing funds for a family emergency or a tragic life event. Some scams, like the Nigerian prince scheme, promise to give you money if you just send your bank account information or pay a small processing fee. Always be cautious about providing personal information or sending money.