Box Shield Suspicious Alert Triggered

AnalysisType: rule
Filename: box_suspicious_login_or_session.py
RuleID: "Box.Shield.Suspicious.Alert"
DisplayName: "Box Shield Suspicious Alert Triggered"
Enabled: true
LogTypes:
  - Box.Event
Tags:
  - Box
  - Initial Access:Valid Accounts
Reports:
  MITRE ATT&CK:
    - TA0001:T1078
Severity: High
Description: >
  A user login event or session event was tagged as medium to high severity by Box Shield.
Reference: https://developer.box.com/guides/events/shield-alert-events/
Runbook: >
  Investigate whether this was triggered by an expected user event.
SummaryAttributes:
  - event_type
  - ip_address
Tests:
  - Name: Regular Event
    ExpectedResult: false
    Log:
      {
        "type": "event",
        "additional_details": '{"key": "value"}',
        "created_by":
          {
            "id": "12345678",
            "type": "user",
            "login": "ceo@example",
            "name": "Bob Cat",
          },
        "event_type": "DELETE",
      }
  - Name: Suspicious Login Event
    ExpectedResult: true
    Log:
      {
        "type": "event",
        "additional_details": '{"shield_alert":{"rule_category":"Suspicious Locations","risk_score":60,"user":{"email":"bob@example"}}}',
        "created_by":
          {
            "id": "12345678",
            "type": "user",
            "login": "bob@example",
            "name": "Bob Cat",
          },
        "event_type": "SHIELD_ALERT",
        "source": { "id": "12345678", "type": "user" },
      }
  - Name: Suspicious Session Event
    ExpectedResult: true
    Log:
      {
        "type": "event",
        "additional_details": '{"shield_alert":{"rule_category":"Suspicious Sessions","risk_score":70,"alert_summary":{"description":"First time in prior month user connected from ip 1.2.3.4."},"user":{"email":"bob@example"}}}',
        "created_by":
          {
            "id": "12345678",
            "type": "user",
            "login": "bob@example",
            "name": "Bob Cat",
          },
        "event_type": "SHIELD_ALERT",
        "source": { "id": "12345678", "type": "user" },
      }
  - Name: Suspicious Session Event - Low Risk
    ExpectedResult: false
    Log:
      {
        "type": "event",
        "additional_details": '{"shield_alert":{"rule_category":"Suspicious Sessions","risk_score":10,"alert_summary":{"description":"First time in prior month user connected from ip 1.2.3.4."},"user":{"email":"bob@example"}}}',
        "created_by":
          {
            "id": "12345678",
            "type": "user",
            "login": "bob@example",
            "name": "Bob Cat",
          },
        "event_type": "SHIELD_ALERT",
        "source": { "id": "12345678", "type": "user" },
      }


# ------ paired body: box_suspicious_login_or_session.py ------

from panther_base_helpers import deep_get
from panther_box_helpers import box_parse_additional_details

SUSPICIOUS_EVENT_TYPES = {
    "Suspicious Locations",
    "Suspicious Sessions",
}


def rule(event):
    if event.get("event_type") != "SHIELD_ALERT":
        return False
    alert_details = box_parse_additional_details(event).get("shield_alert", {})
    if alert_details.get("rule_category", "") in SUSPICIOUS_EVENT_TYPES:
        if alert_details.get("risk_score", 0) > 50:
            return True
    return False


def title(event):
    details = box_parse_additional_details(event)
    description = deep_get(details, "shield_alert", "alert_summary", "description", default="")
    if description:
        return description
    return (
        f"Shield medium to high risk, suspicious event alert triggered for user "
        f"[{deep_get(details, 'shield_alert', 'user', 'email', default='<UNKNOWN_USER>')}]"
    )