http://seclists.org/nmap-hackers/2011/5

Hi Folks. I’ve just discovered that C|Net’s Download.Com site has
started wrapping their Nmap downloads (as well as other free software
like VLC) in a trojan installer which does things like installing a
sketchy “StartNow” toolbar, changing the user’s default search engine
to Microsoft Bing, and changing their home page to Microsoft’s MSN.

The way it works is that C|Net’s download page (screenshot attached)
offers what they claim to be Nmap’s Windows installer. They even
provide the correct file size for our official installer. But users
actually get a Cnet-created trojan installer. That program does the
dirty work before downloading and executing Nmap’s real installer.

Download.com is software hell.