sublimemediumRule

Attachment: Calendar invite with Google redirect and invoice request

Detects calendar file attachments containing Google redirect URLs in the location field combined with invoice-related language in the message body.

MITRE ATT&CK

T1566 T1566.001 T1566.002 T1598 T1534 T1656

initial-access

Detection Query

type.inbound
and any(attachments,
        (
          .file_extension in~ ('ics')
          or .content_type in ("application/ics", "text/calendar")
        )
        and regex.icontains(file.parse_text(.).text,
                            'LOCATION[^:]*:.{1,300}google\.com/url'
        )
)
and any(ml.nlu_classifier(body.current_thread.text).topics,
        .name == "Request to View Invoice" and .confidence == "high"
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Raw Content

name: "Attachment: Calendar invite with Google redirect and invoice request"
description: "Detects calendar file attachments containing Google redirect URLs in the location field combined with invoice-related language in the message body."
type: "rule"
severity: "medium"
source: |
  type.inbound
  and any(attachments,
          (
            .file_extension in~ ('ics')
            or .content_type in ("application/ics", "text/calendar")
          )
          and regex.icontains(file.parse_text(.).text,
                              'LOCATION[^:]*:.{1,300}google\.com/url'
          )
  )
  and any(ml.nlu_classifier(body.current_thread.text).topics,
          .name == "Request to View Invoice" and .confidence == "high"
  )

attack_types:
  - "Credential Phishing"
  - "BEC/Fraud"
tactics_and_techniques:
  - "Open redirect"
  - "Social engineering"
detection_methods:
  - "File analysis"
  - "Natural Language Understanding"
  - "URL analysis"
id: "8ea3cff8-f2ee-5190-8530-a79beab60a3b"