alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET POLICY ZIP file download"; flow:established; content:"PK|0304|"; byte_test:1, <=, 0x14, 0, string, hex; content:"|00 00 00|"; distance:0; reference:url,zziplib.sourceforge.net/zzip-parse.print.html; classtype:misc-activity; sid:2000428; rev:10; metadata:created_at 2010_07_30, confidence High, signature_severity Informational, updated_at 2019_07_26;)