alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET ADWARE_PUP FLV/Youtube Downloader Install Activity"; flow:established,to_server; http.request_line; content:"GET /images/downloader/pixel.gif?action=install&"; startswith; content:"&lngid="; content:"cid="; content:"&kt=flvd"; fast_pattern; http.header_names; content:!"|0d 0a|Referer|0d 0a|"; reference:md5,3af4b637e16922fdceaff00d64e98f53; classtype:pup-activity; sid:2031082; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_10_22, deployment Perimeter, performance_impact Low, confidence High, signature_severity Minor, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_10_22;)