The phishing campaign began in April and was discovered by Netskope researchers. The hackers they send phishing emails, which are supposed to include an invoice and ask users to open an ISO file to see more details.
This ISO file transfers the malicious payload, which is either LokiBot either the Nanocore. Both malicious software provide attackers with backdoors on infected Windows computers and give them ability to they steal data, but also to install other payloads.
The researchers said they have detected 10 variations of the campaign with different ISO images and emails.
The images that are usually sent are 1MB with 2MB, but media includes an executable, which releases the actual malicious payload.
Nowadays, most phishing campaigns, using trojan to attack, are becoming more targeted and attackers are developing more and more sophisticated payloads. This campaign, however, shows that even a commercial malware, used in simple phishing emails, continues to be threatening for organizations and companies.
This is especially true for department employees, who often need to open messages from unknown senders.
One of Netskope's researchers, Abhinav Singh, said the email and attachment review that was in place showed that hackers were primarily targeting company employees, especially those working in the finance department. This shows that the attackers had financial incentives.
The advice given by the researcher to users is to be very careful with any email that may seem suspicious and give even more caution in the attachments, that exist inside, especially those that come from unreliable sources.