Attachment: HTML smuggling with embedded base64-encoded ISO

type.inbound
and any(attachments,
        (
          .file_extension in~ ("html", "htm")
          or .file_extension in~ $file_extensions_common_archives
          or .file_type == "html"
        )
        and any(file.explode(.),
                any(.scan.strings.strings,
                    strings.ilike(.,
                                  // Base64 encoded ISOs
                                  "*SVNPIDk2NjAvSEZT*",
                                  "*MTk5MyBFLllPVU5HREFMRQ*",
                                  // Reversed base64 encoded ISOs
                                  "*TZESvAjN2kDIPNVS*",
                                  "*QRMFERH5UVPllLFByM5kTM*"
                    )
                )
        )
)