No, it is not a Mozilla security message, it's a fake scan. Do not download anything from that website. Look in the Windows Task Manager > Processes tab and kill the process that is running that fake scan.

That is malware masquerading as an anti-virus product. By clicking on the screen you have probably infected your system. You probably picked it up on an infected web site. Do a thorough malware scan. Download, install and update as many of the following as possible until your infections are cleaned. #The '''<u>free versions</u>''' of these scanners will detect infections and clean your system; no need to purchase #'''<u>Different malware scanners detect some malware that other scanners do not.</u>''' #If you are unable to download the malware programs, #* change the name of the installer program before saving the download to your hard drive, and #* once installed, go to the installation folder for the program and change the name of the program executable file (i.e., for Malwarebytes Anti-Malware, change mbam.exe to xyz-mb.exe), then update the program and run the scan. #* you may need to download on an un-infected computer, change the name of the installer program, copy the installer to a CD or USB thumb drive, and transport to your system for installation. #Some stubborn malware will need to be removed in '''Windows Safe Mode with Networking'''. See: #*http://www.pbcomp.com.au/using-windows-safe-mode.html #*http://www.malwarehelp.org/restart-into-safe-mode-how-to-2010.html *Malwarebytes' Anti-Malware - http://www.malwarebytes.org/mbam.php *SuperAntispyware - http://www.superantispyware.com/ *AdAware - http://www.lavasoftusa.com/software/adaware/ *Spybot Search & Destroy - http://www.safer-networking.org/en/index.html *Windows Defender - http://www.microsoft.com/windows/products/winfamily/defender/default.mspx *Dr. Web Cureit - http://www.freedrweb.com/cureit/ If these don't find or can't clear the infection(s), post in one of these forums for specialized malware removal help: #Read and follow their rules for posting #Follow their instructions '''to the letter''' #Be patient; you are put in a queue and you will get a response when they get to your post *http://bleepingcomputer.com *http://www.spywareinfoforum.com/ *http://www.spywarewarrior.com/index.php *http://forum.aumha.org/ -------------------------------- <br /> The information submitted with your question indicates that you have out of date plugins with known security issues that should be updated. To see the plugins submitted with your question, click "More system details..." to the right of your original question post. * Next Generation Java Plug-in 1.6.0_20 for Mozilla browsers #'''Check your plugin versions''': http://www.mozilla.com/en-US/plugincheck/ #*'''Note: plugin check page does not have information on all plugin versions''' #'''Update Java:''' #* Download and update instructions: https://support.mozilla.com/en-US/kb/Using+the+Java+plugin+with+Firefox #* Removing old versions (if needed): http://www.java.com/en/download/faq/remove_olderversions.xml #* Remove multiple Java Console extensions (if needed): http://kb.mozillazine.org/Java#Multiple_Java_Console_extensions #* After the installation, start Firefox and check your version again.