alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE W32/Trojan-Gypikon Server Check-in Response"; flow:established,from_server; dsize:16; content:"|85 19 00 00 25 04 00 00 00 00|"; content:"|40 00 00 00 00|"; distance:1; within:6; reference:md5,f27bf471d2f2c0a76331d25fc4761e10; reference:md5,792b725b6a2a52e4eecde846b39eea7d; classtype:trojan-activity; sid:2018130; rev:3; metadata:created_at 2014_02_13, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)