[Mr.Kurd]

Pretty sure nearly every AV would pick it up in secondary analysis, even Avast DeepScreen
It's just too obvious.

I think so too.

It's pretty much well-known and If not detected via signature-based analysis, any behavioral and/or heuristic methods may well pick It up.

Snort rules for meterpreter are pretty commonplace too, this is why I recommend using reverse_https over reverse_http

Example:

Code:

# Snort rules by Didier Stevens (http://DidierStevens.com)
# 2015/04/30
# I start numbering my rules at SID 1618000
#alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Metasploit User Agent String"; flow:to_server,established; content:"User-Agent|3a| Mozilla/4.0 (compatible\; MSIE 6.0\; Windows NT 5.1)|0d 0a|"; http_header; classtype:trojan-activity; reference:url,blog.didierstevens.com/2015/03/16/quickpost-metasploit-user-agent-strings/; sid:1618000; rev:1;)
alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Metasploit User Agent String"; flow:to_server,established; content:"User-Agent|3a| Mozilla/4.0 (compatible\; MSIE 6.1\; Windows NT)|0d 0a|"; http_header; classtype:trojan-activity; reference:url,blog.didierstevens.com/2015/03/16/quickpost-metasploit-user-agent-strings/; sid:1618001; rev:1;)
#alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Metasploit User Agent String"; flow:to_server,established; content:"User-Agent|3a| Mozilla/4.0 (compatible\; MSIE 7.0\; Windows NT 6.0)|0d 0a|"; http_header; classtype:trojan-activity; reference:url,blog.didierstevens.com/2015/03/16/quickpost-metasploit-user-agent-strings/; sid:1618002; rev:1;)
alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Metasploit User Agent String"; flow:to_server,established; content:"User-Agent|3a| Mozilla/4.0 (compatible\; MSIE 7.0\; Windows NT 6.0\; Trident/4.0\; SIMBAR={7DB0F6DE-8DE7-4841-9084-28FA914B0F2E}\; SLCC1\; .N|0d 0a|"; http_header; classtype:trojan-activity; reference:url,blog.didierstevens.com/2015/03/16/quickpost-metasploit-user-agent-strings/; sid:1618003; rev:1;)
alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Metasploit User Agent String"; flow:to_server,established; content:"User-Agent|3a| Mozilla/4.0 (compatible\; Metasploit RSPEC)|0d 0a|"; http_header; classtype:trojan-activity; reference:url,blog.didierstevens.com/2015/03/16/quickpost-metasploit-user-agent-strings/; sid:1618004; rev:1;)
#alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Metasploit User Agent String"; flow:to_server,established; content:"User-Agent|3a| Mozilla/5.0 (Windows\; U\; Windows NT 5.1\; en-US) AppleWebKit/525.13 (KHTML, like Gecko) Chrome/4.0.221.6 Safari/525.13|0d 0a|"; http_header; classtype:trojan-activity; reference:url,blog.didierstevens.com/2015/03/16/quickpost-metasploit-user-agent-strings/; sid:1618005; rev:1;)
alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Metasploit User Agent String"; flow:to_server,established; content:"User-Agent|3a| Mozilla/5.0 (compatible\; Googlebot/2.1\; +http://www.google.com/bot.html)|0d 0a|"; http_header; classtype:trojan-activity; reference:url,blog.didierstevens.com/2015/03/16/quickpost-metasploit-user-agent-strings/; sid:1618006; rev:1;)
#alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Metasploit User Agent String"; flow:to_server,established; content:"User-Agent|3a| Mozilla/5.0 (compatible\; MSIE 10.0\; Windows NT 6.1\; Trident/6.0)|0d 0a|"; http_header; classtype:trojan-activity; reference:url,blog.didierstevens.com/2015/03/16/quickpost-metasploit-user-agent-strings/; sid:1618007; rev:1;)

So What u say about reeverse_tcp i use it usually.