Yahoo Mail logo is displayed on a smartphone's screen in front of code in this illustration picture, October 6, 2016. Reuters/Dado Ruvic

Another Yahoo data breach has been uncovered by Yahoo Inc recently. The company warned on Wednesday that data of more than one billion user accounts (double the number from its last cyber attack) were affected this time.

The newly reported Yahoo data breach occurred in 2013, about which the company learned from law enforcement recently. Yahoo, as of now, has not determined the means through which the data of one billion accounts was stolen. However, Yahoo said that a third party was involved in this.

This Yahoo data breach is different from the one reported earlier

The recently reported Yahoo data breach is different from the one that was reported in September earlier this year, which was a 2014 hack involving data breach of 500 million accounts.

Payment card data and bank account information are safe

Yahoo reported that the stolen information "may have included" names, e-mail addresses, dates of birth, telephone numbers and hashed passwords. Furthermore, it doubted that encrypted or unencrypted security questions and answers might have also leaked in some cases. However, the company said that the payment card data and bank account information were safe as they were not stored in the system that the company believed was affected.

Affected account holders will be contacted

Yahoo has stated that the affected account holders will be contacted. Furthermore, all the customers are required to change their passwords. During last Yahoo data breach, the company had only recommended its customers to change their passwords. However, this time Yahoo is firm about changing of the passwords.

Yahoo’s business deals suffer

Yahoo data breach has put the company’s deal Verizon Communication Inc in doubt. When news about the last data breach broke out, Verizon Communication said in October that it might withdraw the agreement of buying Yahoo's core internet business involving advertising, search, content and mobile activities for US$4.83 billion (AU$6.51 billion).

Now after the announcement of another Yahoo data breach, Verizon said in a statement, “We will review the impact of this new development before reaching any final conclusions."

Meanwhile, Verizon Enterprise Solutions, which is a division of Verizon Communications, has been recently named as one of six service providers that will provide telecommunications services to the Australian Federal Government.

Yahoo’s shares are down

Hours after the company announced the news of Yahoo data breach, the company’s shares were down by 2.4 percent to US$39.91 (AU$ 53.74) in extended trading.