Attachment: HTML smuggling with high entropy and other signals

type.inbound
and any(attachments,
        (
          .file_extension in~ ("html", "htm", "shtml", "dhtml")
          or .file_extension in~ $file_extensions_common_archives
          or .file_type == "html"
        )
        and any(file.explode(.),
                .scan.entropy.entropy >= 5
                and any(.scan.strings.strings,
                        regex.icontains(., "fromCharCode")
                        and regex.icontains(., "parseInt")
                        and regex.icontains(., "charCodeAt")
                        and regex.icontains(., '(\\x0.*?){50}')
                )
        )
)