A string of data thefts targeting North American mining companies and casinos are extorting as much as $620,000 from victims.

A campaign attributed to the FIN7 attackers targets restaurants with phishing emails and infected RTF Word documents that carry out fileless malware attacks.

Researchers say fileless in-memory malware attacks have become a major nuisance to businesses and have become even harder to detect and defend.

Two recent fileless malware campaigns targeting financial institutions, government agencies and other enterprises have been linked to the same attack group.