alert tcp $EXTERNAL_NET any <> $HOME_NET any (msg:"ET POLICY hidden zip extension .scr"; flow:established; content:"|50 4b 03 04|"; byte_jump:2,22,relative,little, post_offset 2; content:".scr"; distance:-4; within:4; classtype:suspicious-filename-detect; sid:2001408; rev:14; metadata:created_at 2010_07_30, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)