alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"ET WEB_CLIENT DXF Extension File Detection Access Flowbit Set"; flow:established,to_client; flowbits:set,DXF.Ext.Access; content:"|20 20 30|"; content:"|0A 53 45 43 54 49 4F 4E|"; within:10; content:"|20 20 32|"; within:5; content:"|48 45 41 44 45 52|"; distance:0; content:"|0a|"; within:2; flowbits:noalert; classtype:not-suspicious; sid:2012152; rev:2; metadata:affected_product Web_Browsers, affected_product Web_Browser_Plugins, attack_target Client_Endpoint, created_at 2011_01_06, deployment Perimeter, confidence Medium, signature_severity Major, tag Web_Client_Attacks, updated_at 2019_07_26;)