#alert tcp $HOME_NET any -> 61.152.93.13 $HTTP_PORTS (msg:"BLEEDING-EDGE TROJAN Backdoor.Graybird.O Calling Home 61.152.93.13"; flags: S,12; threshold:type limit, track by_src, count 1, seconds 60; reference:url,securityresponse.symantec.com/avcenter/venc/data/backdoor.graybird.o.html; classtype:trojan-activity; sid:2002359; rev:2;)