Detection rules › Sublime MQL

Service abuse: Google Calendar notification with callback scam language

Severity
medium
Type
rule
Source
github.com/sublime-security/sublime-rules

Detects messages sent from Google's legitimate calendar notification service that contain callback scam language, indicating potential abuse of the calendar sharing feature to distribute fraudulent content.

Threat classification

Sublime's own taxonomy (not MITRE ATT&CK).

CategoryValues
Attack typesCallback Phishing
Tactics and techniquesICS Phishing, Out of band pivot, Social engineering

Event coverage

Rule body MQL

type.inbound
and sender.email.email == 'calendar-notification@google.com'
and any(ml.nlu_classifier(body.current_thread.text).intents,
        .name == "callback_scam" and .confidence != "low"
)

Detection logic

Scope: inbound message.

Detects messages sent from Google's legitimate calendar notification service that contain callback scam language, indicating potential abuse of the calendar sharing feature to distribute fraudulent content.

  1. inbound message
  2. sender.email.email is 'calendar-notification@google.com'
  3. any of ml.nlu_classifier(body.current_thread.text).intents where all hold:
    • .name is 'callback_scam'
    • .confidence is not 'low'

Inspects: body.current_thread.text, sender.email.email, type.inbound. Sensors: ml.nlu_classifier.

Indicators matched (2)

FieldMatchValue
sender.email.emailequalscalendar-notification@google.com
ml.nlu_classifier(body.current_thread.text).intents[].nameequalscallback_scam