alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING Suspicious Terse Request for .bmp"; flow:established,to_server; content:".bmp|20|HTTP/1.1|0d 0a|Host|3a 20|"; fast_pattern; http.method; content:"GET"; http.uri; content:".bmp"; endswith; http.header_names; content:!"Accept"; content:!"User-Agent"; content:!"Cache-"; content:!"Pragma"; content:!"Referer"; classtype:bad-unknown; sid:2030384; rev:1; metadata:affected_product Any, attack_target Client_Endpoint, created_at 2020_06_24, deployment Perimeter, confidence Medium, signature_severity Informational, updated_at 2020_06_24;)