Classification:

attack

Tactic:

TA0001-initial-access

Technique:

T1566-phishing

VIEW RULE IN DATADOG VIEW SIGNALS

Goal

Detects when multiple phishing emails are received from an external sender within a short period, which may indicate an ongoing phishing campaign targeting users.

Strategy

This rule monitors inbound emails and raises an alert when multiple phishing emails originate from an external sender, potentially signalling a coordinated attack or a compromised sender account. Emails that are quarantined or deleted do not raise an alert.

Triage and Response

1. Review the sender email address {{@event.entity.entity_payload.from_email}} to determine legitimacy.
2. Quarantine or delete the detected phishing emails to prevent user interaction.
3. Investigate if the sender is a compromised legitimate account or part of a larger phishing campaign.
4. If confirmed malicious, begin the security incident response process.