The XF97/Yagnuul-A virus can infect users' .xls spreadsheets once the attachment is opened. The virus deploys an infected fantasy league file on the computer's hard drive and may also modify a user's data, according to an alert Monday from security company Sophos.
"Fantasy football-like leagues have been set up in offices across the (U.K.), and fans often keep track of how well they are doing by using Excel spreadsheets," Graham Cluley, Sophos senior technology consultant, said in a statement. "Every computer user needs to take great care not to fall foul of malware like the Yagnuul virus."
The virus relies on social engineering to entice people to open the attachment, said Ron O'Brien, a Sophos senior security analyst. He added that fantasy league players often do not know each other and, as a result, are prone to opening attachments from strangers who claim to be a league member.
Yagnuula, however, is currently a low-risk virus because a number of security companies have put out antivirus software to contain it, O'Brien noted.