Online Malware Scanner for websites
Scan a folder with clamscan
maldet
https://opentip.kaspersky.com
https://sitecheck.sucuri.net
Tools
https://remnux.org/
Forums
http://www.virusinfo.info
http://www.rootkit.com
http://www.gmer.net
Blogs
https://www.securelist.com/en/threats/detect?chapter=83
http://www.youtube.com/watch?v=Q5cT3YHKVsY