Although there is a possibility you were ‘hacked’, it is far more likely that your address was compromised by one of the powerful spam bot networks. They have the ability to crack passwords, especially weak ones. They can also ‘spoof’ the addresses in the From: area to make it more likely that they will be opened. Remember all those who use the To: or CC: heading rather than BCC: for addresses? Remember all those who forward e-mails with countless addresses still in them? They open all those addresses to spammers – all it takes is one infected computer down the line somewhere! Spammers have programs just to ‘harvest’ e-mail addresses. Your account has been seriously compromised, and more of this type of letter will keep happening. It may not even be your own computer that was infected. Nonetheless, act promptly!
Yahoo’s advice is to change your password, but there are several more security settings to change than just your password. This Help page has more information, stated clearly, with several links to clarify the steps.http://help.yahoo.com/kb/index?page=cont…
1. FIRST, check that the alternate e-mail address/mobile phone number is still yours, under Options, Mail Options, Account Information, but then change the alternate address! (so the hacker will not be notified of the change). Check the ‘Reply To:’ address as well to be sure it is still yours.
Then change both your password AND your secret questions and answers. Make the password a long, strong one with mixed characters! Length = Strength for passwords! Start with a sentence and make substitutions with numbers, symbols and punctuation. Go to “Update password-reset info” to change your Secret Questions and Answers. Make sure they are unchangeable, unique, and easy for you to remember. For a Yahoo account, you can change your password at https://edit.yahoo.com/config/change_pw. If you can no longer access your account, you can get a new password at https://edit.yahoo.com/forgotroot/.
See http://strongpasswordgenerator.com/ for more tips on creating a strong password(and what NOT to use)
2. *** If spam mail was sent to any of your contacts, apologize, and notify all your contacts NOT to open short e-mails, especially those with no subject, and definitely not to click any links. Warn them to change their passwords and scan for malware too, just in case. (The limit is 100 addresses per mail, and 200 per hour, but send to far fewer than that in each message, just in case you trigger Yahoo’s spam ‘suspicious activity’ detector.) Set up an alternate ‘alias’ account to use instead. This allows you to use a different address for sending, but still keep all saved mails and contacts and the first address active too for incoming mail. Your friends can trust this new address! There is a choice of address in an arrow in the From: box. Also add a signature to your mail so your friends will be sure the mail is really from you …http://edit.yahoo..com/config/list_alias (alternate address)
3. When the password doesn’t work and the security questions have been changed, go to https://edit.yahoo.com/forgotroot/
After filling in your ID and password as usual, click the proper category of ‘I can’t sign in’ [Account compromised] to send an email with all of the information an agent needs to respond within 12-24 hours, hopefully …
– Give them your identity using your country, and the same alternate email address or mobile phone number and Security Questions and Answers that you provided during registration or the last time you edited. You might also be asked for your birthday, ZIP or postal code at the time you last updated.
Check your alternate e-mail for a response. Sometimes the mail will be found in the Spam folder instead. If you didn’t register an alternate e-mail address or mobile phone number previously, you will be out of luck, and can only use the direct phone line method: Call 866-850-4303 toll-free (Open 7 days a week, 6 a.m. – 6 p.m. Pacific Standard Time) Be prepared for a VERY long wait, even hours …
4. Read the Yahoo Mail Blog entry for December 8th, 2011 for all possible steps, including if you forgot or do not have secret questions and answers …http://www.ymailblog.com/
Answers is a Jungle