alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"ET SHELLCODE Possible UTF-8 encoded Shellcode Detected"; flow:from_server,established; content:"%u"; nocase; isdataat:2; content:!"|0A|"; within:2; content:!"|20|"; within:2; pcre:"/(%U([0-9a-f]{2})){6}/i"; classtype:trojan-activity; sid:2003173; rev:7; metadata:created_at 2010_07_30, confidence Medium, signature_severity Major, updated_at 2019_07_26;)