EasyDoc Converter - AVOID
Tony Still If you have Gatekeeper enabled, it will be flagged should anything try to install it - just say no.
If you don't have Gatekeeper enabled, give yourself a gentle telling-off and then:
Go to System Preferences->Security&Privacy->General and set "Allow apps downloaded from:" to "Mac App Store and identified developers" (or just "Mac App Store"). This causes the OS to prompt you when a newly downloaded app first wants to run; unless you're very sure of it, say 'no' whenever this prompt appears.
Another class of nasties currently in circulation pretends to be a .jpg file (or other common file type), usually delivered inside a zip archive. It's actually a script that does bad things. The giveaway here is that it uses an obscure feature of the underlying OS that treats any file whose name ends in a space (that is conveniently invisible) as an executable (script). Gatekeeper will flag this too so just say no again.
If you do a Finder 'Get Info', you'll see that the "Kind" is executable (not JPEG image or whatever); if you investigate further you'll see the trailing space on the file name. This one is being called OSX/Keydnap, likely to be copycats too soon.
Usual security guidance also applies: don't accept downloads from any remotely dodgy web sites - go to the trusted home site of the app. If you've never heard of the app, research it before downloading it. Don't use pirated software, it's a favourite delivery mechanism for malware (apart from the fact that it's illegal and you're stealing the author's livelihood).
Enjoy...