A fresh round of email warnings for Yahoo account holders has been sent; however, cybercriminals are taking advantage: A new Yahoo breach phishing campaign has been detected that piggybacks on the latest news.

New Warnings for Yahoo Email Account Holders

Yahoo has been sending fresh warnings to account holders explaining that their accounts may have been compromised as a result of the Yahoo cyberattacks in 2013 and 2014. The Yahoo cyberattacks were the largest ever seen, resulting in the theft of 1 billion and 500 million users’ credentials. Yahoo has now confirmed that the attacks involved the use of forged cookies to bypass its security controls.

Yahoo’s CISO Bob Lord has told account holders in the email that “We have connected some of the cookie forging activity to the same state-sponsored actor believed to be responsible for the data theft we disclosed on Sept. 22, 2016.” As was the case in previous Yahoo warnings, accounts should be reviewed for any suspicious activity and users should not click on links or open attachments from unknown senders.

Yahoo Breach Phishing Campaign Detected

Many active Yahoo account holders are concerned about email security following news of the cyberattacks in 2013/2014 and cybercriminals have been quick to take advantage. The fresh round of email warnings has only heightened fears, as well as the risk for account holders. Cybercriminals have been piggybacking on the latest news of account breaches and have been sending their own messages to Yahoo email users. The latest Yahoo breach phishing email campaign play on users’ fears over the security of their accounts. The Yahoo breach phishing emails attempt to fool security conscious account holders into clicking on malicious phishing links and revealing sensitive information.

In the latest round of warnings, Yahoo urged users to take advantage of Yahoo’s password-free security service – the Yahoo Account Key authentication service. The latest round of Yahoo breach phishing emails offer account holders the option of upgrading the security on their accounts as well. To improve take up, the attackers add urgency by saying the target’s account has been temporarily limited for failing an automatic security update. A link is supplied for users to click to re-verify account ownership. If they fail to click on the link and update their details, they will be permanently locked out of their account.

The Yahoo breach phishing campaign is likely to claim many victims, although the phishing emails are fairly easy to identify as fake. The emails appear to have come from an account called ‘Mail’, although checking the actual email address will reveal that the email was not sent from a domain used by Yahoo. There are also some errors with the structure of the email. Slight grammatical errors are a tell-tale sign that the emails are not genuine.

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However, not all Yahoo breach phishing emails contain errors. Some have been highly convincing. Users are therefore advised to exercise extreme caution when using their Yahoo accounts and to be on high alert for Yahoo breach phishing emails.

Cost of the Yahoo Cyberattacks

The Yahoo cyberattacks of 2013 and 2014 have cost the company dearly. While it is unclear what the final cost of the Yahoo cyberattacks will be, it will certainly be well in excess of $250 million – That is the price reduction Verizon Communications is seeking following the revelation that Yahoo account holders’ credentials were stolen in the two massive cyberattacks reported last year. The purchase price of $4.8 billion, which was agreed in the summer of 2016, is to be reduced. There was talk that the deal may even not go ahead as a result of the Yahoo cyberattack revelations. While Yahoo will not want a price reduction, there are likely to be a few sighs of relief. Verizon were rumored to be looking for a $1 billing reduction in the price just a few weeks back.