alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Possible .jpg download by VBA macro (SET) M1"; flow:established,to_server; flowbits:set,ET.vba-jpg-dl; flowbits:noalert; http.method; content:"GET"; http.uri; content:".jpg"; pcre:"/\.jpg(?:\?\d+)?$/"; http.header; strip_pseudo_headers; header_lowercase; content:"accept|3a 20 2a 2f 2a 0d 0a|accept-encoding|3a 20|gzip|2c 20|deflate|0d 0a|user-agent|3a 20|Mozilla|2f|4|2e|0|20 28|compatible|3b 20|MSIE|20|7|2e|0|3b 20|Windows|20|NT"; startswith; fast_pattern; http.header_names; to_lowercase; content:!"|0d 0a|referer|0d 0a|"; content:!"|0d 0a|accept-language|0d 0a|"; classtype:not-suspicious; sid:2022220; rev:6; metadata:created_at 2015_12_05, confidence Low, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_05_01;)