alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE UPX compressed file download possible malware"; flow:established,to_client; file.data; content:"MZ"; startswith; byte_jump:4,58,relative,little; content:"PE|00 00|"; distance:-64; within:4; content:"UPX0"; content:"UPX1"; content:"UPX!"; fast_pattern; classtype:misc-activity; sid:2001046; rev:15; metadata:created_at 2010_07_30, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_11;)