Quoted from here

Traffic analysis has been the primary method of malware identification and thousands of IDS signatures developed are the daily proof. Signatures definitely help but ability to visually recognize malware traffic patterns and see the trends when they change has been always an important skill for anyone tasked with network defense. The number of malware analysis blogs and papers is overwhelming and it is difficult to keep track of malware features if you don't have access to a well designed and constantly updated malware database. This started as "personal notes" spreadsheet with GET and POST requests for different malware families with information from open sources. We decided others might find it useful too.

VIEW OR DOWNLOAD "MALWARE TRAFFIC PATTERNS" SPREADSHEET

This is truly an exceptional and valuable community tool for researchers. On the same for those interested in these stuffs i.e. for whitehat researchers, here are some useful sites :

malware.lu

DeepEndResearch

Contagiodump

Operational cryptology and virology lab

Modern malware investigations and reviews

XyliBox

Tracking Cybercrime

Malware don't need Coffee

ARF Project

Malware Reconstructor

All the bloggers take the researching quite seriously, are frequently updated and provide and in-dept analysis. More blogs are listed in above blog.