Sublime Security high experimental mql

Attachment: OLE external relationship containing file scheme link to IP address

This rule identifies attachments containing file scheme links pointing to IP Addresses, a common indicator of malware distribution. It applies to various suspicious file extensions and archive formats, aiming to prevent the initiation and execution of malicious software. The rule negates firing on IP addresses governed by RFC1918 or privately allocated space.

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Detection Logic

type.inbound
and any(attachments,
        (
          .file_extension in~ $file_extensions_macros
          or .file_extension in~ $file_extensions_common_archives
          or (
            .file_extension is null
            and .file_type == "unknown"
            and .content_type == "application/octet-stream"
            and .size < 100000000
          )
        )
        and any(file.oletools(.).relationships,
                .target_url.scheme == "file"
                and regex.contains(.target_url.path,
                                   '([0-9]{2,3}\.){3}[0-9]{2,3}'
                )
                and not regex.icontains(.target_url.path,
                                        '(10\.(?:\d{1,2}
| 1\d{2}
| 2[0-4]\d
| 25[0-5])\.(?:\d{1,2}
| 1\d{2}
| 2[0-4]\d
| 25[0-5])\.(?:\d{1,2}
| 1\d{2}
| 2[0-4]\d
| 25[0-5]))
| (172\.(?:1[6-9]
| 2\d
| 3[0-1])\.(?:\d{1,2}
| 1\d{2}
| 2[0-4]\d
| 25[0-5])\.(?:\d{1,2}
| 1\d{2}
| 2[0-4]\d
| 25[0-5]))
| (192\.168\.(?:\d{1,2}
| 1\d{2}
| 2[0-4]\d
| 25[0-5])\.(?:\d{1,2}
| 1\d{2}
| 2[0-4]\d
| 25[0-5]))'
                )
        )
)
and (
  not profile.by_sender().any_messages_benign
  or profile.by_sender().any_messages_malicious_or_spam
)

Field Validations

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