how to check yahoo for a hacked account.
This shows how to view recent login activity.
http://www.blindfiveyearold.com/yahoo-email-hacked
2 year old answer-
This problem is a common one on Answers, several times each day for months. Either your mail was infected by malware (a trojan, not a virus) or spoofed by spammers, or your address was found in someone else's infected computer. The results are the same: that address will need to be changed. This new trojan malware can infect computers and get the address book simply by opening the mail - no click is necessary, so it spreads fast!
- First, check your sent box to be sure these were not being sent from your account as a 'zombie' spambot machine.
- Second, open your profile to be sure your password and secret questions & answers and alternate mails remain the same.
- Third, change all that information to more secure and unusual ones.
- Fourth, read the references below for the best explanations I've ever seen.
- Fifth, this could be a malware attack so do a scan in Safe Mode (Malwarebytes is best). Then delete all System Restore Points before re-booting into normal mode.
- Sixth, set up a new account and new alternate accounts. Do not close the old ones until all information is transferred. Import the Contacts list, and forward important saved mails too.
https://edit.yahoo.com/registration?.int… (new address)
http://edit.yahoo..com/config/list_alias… (alternate address)
- Last, contact everyone with your new address, including your name and 'new address' in the Subject line, as well as an apology to them. Urge ALL of them to use BCC: and delete all addresses when forwarding mail too! Warn them not to click ANY links or even open mail from the old address. (Some malware can infect computers just by opening the mail.)
Changing your password is NOT sufficient, even though that is Yahoo's advice! Use a very strong password (letters, capitals, punctuation, numbers, symbols - the longer the better.) Start with a sentence, and make substitutions. Be sure the result is one you can remember. Change your 'Secret' Questions and Answers too - ones that nobody could guess - Yahoo even allows you to invent your own questions. Change and add all-new alternate e-mail addresses too.