And it strikes again . . . . first, don't assume it's a competitor. It might have even been you, without knowing it, especially if it's hitting all your domains.
Do your site files have
any of the symptoms here [webmasterworld.com]? I'm suspecting they do, you said the "W" word and every encounter I've had with this has two common elements: Wordpress and tiny_mce.
If this is the case, the good news is, your
site doesn't "have a virus," your files have been modified to
spread this thing. This is tedious, but not that difficult to eradicate, details in that link. The most important part: before doing anything, update your AVG, take it OFFLINE, run the scans, then change all your passwords. FTP, WP, Control Panels, everything. Call in a reliable local computer tech if you have to, make sure you're squeaky clean.
Then set out cleaning your site files.
I am not
blaming WP or tiny_mce, the most believable (yet unconfirmed) scenario is that a webmaster (you?) goes to a web site that has this code. Your AVG doesn't catch it. You get a white page, nada, shrug it off, close the window and forget about it. But a malware has just been installed.
It somehow either piggy backs your FTP connection, or just mods WP files locally so when you upload them, they have the JS code pointing to a compromised server to populate.
"Correlation does not mean causation" - I find it interesting WP and tiny_mce are always present when I see it, but this does not mean they are the cause.
