malware

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