Any information on JS:iframe-YF[Trj] (website infection)?

I have just visited a potential customer’s website, and avast free antivirus said it was infected with JS:iframe-YF[Trj]. I can’t find any information about it though. I’ve searched on avast.com and symantec security response, as well as google and duckduckgo but can’t find anything. Thanks.

Similar kind of detection handled here: https://forum.avast.com/index.php?topic=99717.0

Whenever a website with Word Press CMS,
then scan that website here: hackertarget.com/wordpress-security-scan/
and here: http://retire.insecurity.today/#
and here: https://observatory.mozilla.org/

polonus (volunteer website security intelligence analyst and website error-hunter)