alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET EXPLOIT_KIT Unknown_MM - Payload Download"; flow:established,to_client; file_data; content:"PK"; within:2; content:"stealth.exe"; within:60; classtype:exploit-kit; sid:2016377; rev:2; metadata:created_at 2013_02_08, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)