Since 2016, FormBook has been active as a data-stealing malware that affects 4% of enterprises in 2020. It tracks and monitors keystrokes, finds and accesses files, takes screenshots, harvests passwords from various browsers, drops files, downloads, and executes stealthier malware in response to orders from a command-and-control server (C2). The cybercriminals behind these email campaigns used a variety of distribution techniques to deliver this malware, including PDFs, Office Documents, ZIP, RAR, etc.
Researchers in Ukraine have observed a mass distribution of emails with the subject “letter of approval of cash security” among state organizations.
“Attached to the e-mail is the XLS file “support letter.xlsx”, the opening of which will activate the macro, which will download and run the malicious program Formbook/XLoader v2.5 (obviously, the content-bait of the document is not relevant for citizens of Ukraine).” – CERT-UA
The credentials and authentication data on the victim’s system is then stolen and sent to the attacker’s server.