Microsoft has observed that the hacking group known as Evil Corp or TA505 has switched up the tactics in its ongoing phishing campaign to deliver malware by using malicious Excel documents.
The company provided more details on the new campaign in a series of tweets in which its researchers said that the final payload is now being delivered by using an Excel document containing a malicious macro.
Evil Corp has been active since 2014 and the cybercrime group is financially motivated. It is known for targeting retail companies as well as financial institutions by using large malicious spam campaigns powered by the Necurs botnet.
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Researchers from Microsoft Security Intelligence explained how Evil Corp's new campaign works in a tweet, which reads:
“The new campaign uses HTML redirectors attached to emails. When opened, the HTML leads to the download Dudear, a malicious macro-laden Excel file that drops the payload. In contrast, past Dudear email campaigns carried the malware as attachment or used malicious URLs.”
This new campaign marks the first time that Evil Corp has used HTML redirectors as part of its attacks. Previous email campaigns carried out by the group used attachments or malicious download URLs to deliver their malicious payloads.
Evil Corp's latest campaign sends out phishing messages that come with HTML attachments that automatically start downloading the Excel file used to drop the payload. Victims are told to open the Excel document on their computer and to enable editing to access its contents.
Once this is done, the malware will also try to drop a remote access trojan (RAT) known as Grace Wire or FlawedGrace onto a victim's system.
The cybercriminals behind this new campaign even utilized localized HTML files in different languages in order to reach victims from all around the world.
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