If you know of any places that distribute malware for testing/experimentation, post them here. I'll start..
http://kernelmode.info has a Malware forum where tons of samples may be obtained.
https://www.grc.com/malware.htm is Steve Gibson's (GRC / Security Now podcasts, Spinrite creator, coiner of the term malware -- does he really need an introduction?) This part of his site is very new, and only has some CryptoLocker samples as well as a ZEUS/ZBOT sample.