One in 14 e-mails circulated on the Internet containing it as of Monday morning. Around 85 percent of all viruses reported to Sophos are what the company calls Sober-Z, up from around 60 percent last week. The worm first appeared around Nov. 22 using several forms of social engineering to trick users into executing the attachment. Messages purporting to be from the U.S. Federal Bureau of Investigation warn recipients that they have been visiting illegal Web sites and ask them to read a list of attached questions.”]
Source: https://www.csoonline.com/article/2119023/sober-worm-variant-on-the-rise.html