Googling
www.mustangmods.com (
not visiting it) reveals that mustangmods is an image hosting site, and also is now considered to be a site that hosts malware.
I suspect that somewhere in our 100,000+ posts is a post with an image that is stored on the above site. In that way I can see how Google, or your browser, or some software, might inform you that anausa.org/forum contains image links to a site which in turn contains links to malware.
I don't think there is any risk to you, as long as you don't go to mustangmods, or download anything from there. This is an interesting issue, though. Should the ANA Forum block posting image links to such an image host, because some one has determined that they also host malware? Is that done retroactively as well? What would happen if Photobucket suddenly got rated? I don't know the answer to that question.
Steve