High Severity

Attachment: Personalized fake order/invoice file naming pattern

Labels

Callback Phishing

Social engineering

Description

Detects inbound messages from free webmail senders with fake order confirmation or overdue invoice lures, carrying an attachment whose file name is dynamically personalized with the recipient's email local part and follows a structured pattern (date-like prefix, recipient identifier, and an alphanumeric code). This naming convention is used to make the attachment appear as a legitimate, individually generated invoice or receipt tailored to the target.

References

No references.

Sublime Security

Created Sep 28th, 2026 • Last updated Sep 28th, 2026

Feed Source

Sublime Core Feed

Source

GitHub

type.inbound
and recipients.to[0].email.local_part is not null
and recipients.to[0].email.local_part != ""
and any(attachments,
        strings.count(.file_name, '_') == 2
        and strings.icontains(.file_name,
                              strings.concat('_',
                                             recipients.to[0].email.local_part,
                                             '_'
                              )
        )
        and regex.match(.file_name, '202\d{5}_[^\_]+_[A-Z0-9]+\..*')
)

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