alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Possible malicious zipped-executable"; flow:established,from_server; file_data; content:"PK|01 02|"; within:4; content:".xla"; nocase; content:"PK|05 06|"; within:52; content:"|01 00 01 00|"; distance:4; within:4; classtype:trojan-activity; sid:2018086; rev:5; metadata:created_at 2014_02_07, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)