Hackers have built a list of 711.5 million email addresses to spread banking malware across the web.
It was discovered by a Paris-based security expert who goes by the online name Benkow, and was publicised by ZDnet.
The attackers’ spambot operates in two ways. If it knows only the email address, it will attempt to trick the owner into revealing more information. If it knows the password too, it will hijack accounts to support the campaign.
The hackers have even gathered some accounts’ simple mail transfer protocol server and port settings to fool spam-detectors into accepting their messages.
The spambot has also hidden in its emails pixel-sized images that gather information about victims’ computers. When follow up emails are sent, the malware required to infect that device can then be attached and deployed.
Benkow suggested the data may have been harvested from previous leaks, a Facebook phishing campaign and sales of hacking victims’ data.
People can check to see if their data has been breached via the Have I Been Pwned service. It’s not currently possible to check if an account has been hijacked. Affected users are advised to change their passwords.