---
title: Newly Observed FortiGate Alert
description: This rule detects FortiGate alerts that are observed for the first time in the previous 5 days of alert history. Analysts can use this to prioritize triage...
url: https://www.elastic.co/docs/reference/security/prebuilt-rules/rules/cross-platform/newly_observed_fortigate_alert
products:
  - Elastic Security
---

# Newly Observed FortiGate Alert
This rule detects FortiGate alerts that are observed for the first time in the previous 5 days of alert history.
Analysts can use this to prioritize triage and response.
**Rule type**: esql
**Rule indices**:
**Rule Severity**: critical
**Risk Score**: 99
**Runs every**: 5m
**Searches indices from**: `now-7205m`
**Maximum alerts per execution**: 100
**References**:
- [[https://www.elastic.co/docs/reference/integrations/fortinet_fortigate](https://www.elastic.co/docs/reference/integrations/fortinet_fortigate)](https://www.elastic.co/docs/reference/integrations/fortinet_fortigate)

**Tags**:
- Use Case: Threat Detection
- Rule Type: Higher-Order Rule
- Resources: Investigation Guide
- Domain: Network
- Data Source: Fortinet
- Noise: Medium
- Performance: Normal
- Rule Type: ES|QL

**Version**: 4
**Rule authors**:
- Elastic

**Rule license**: Elastic License v2

## Investigation guide


## Triage and analysis


### Investigating Newly Observed Fortigate Alert

This rule surfaces newly observed, low-frequency high severity FortiGate alerts within the last 5 days.
Because the alert has not been seen previously, it should be prioritized for validation to determine whether it represents a true compromise or rare benign activity.

### Investigation Steps

- Identify the source address, affected host and review the associated message to understand the alert.
- Validate the source address under which the activity occurred and assess whether it aligns with normal behavior.
- Refer to the specific alert details like event.original to get more context.


### False Positive Considerations

- Vulnerability scanners and pentesting.
- Administrative scripts or automation tools can trigger detections when first introduced.
- Development or testing environments may produce one-off behaviors that resemble malicious techniques.


### Response and Remediation

- If the activity is confirmed malicious, isolate the affected host to prevent further execution or lateral movement.
- Terminate malicious processes and remove any dropped files or persistence mechanisms.
- Collect forensic artifacts to understand initial access and execution flow.
- Patch or remediate any vulnerabilities or misconfigurations that enabled the behavior.
- If benign, document the finding and consider tuning or exception handling to reduce future noise.
- Continue monitoring the host and environment for recurrence of the behavior or related alerts.


## Rule Query

```esql
FROM logs-fortinet_fortigate.*, filebeat-* metadata _id

| WHERE event.module == "fortinet_fortigate" and event.action in ("signature", "ssl-anomaly") and
  message is not null and event.category != "authentication" and
  message != "Connection Failed" and not message like "Web.Client: *" and
  not message like "Network.Service: *" and not message like "General.Interest*" and not message like "Update: *" and
  not message like "tcp_reassembler*" and not message like "a-ipdf*" and not message like "Video*" and not message like "nbss_decode*" and
  not message like "name_server*" and not message like "misc*" and not message like "Collaboration*" and not message like "Business*" and
  not message like "Cloud.IT*" and not message like "Mobile*"

| STATS Esql.alerts_count = count(*),
        Esql.first_time_seen = MIN(@timestamp),
        Esql.distinct_count_src_ip = COUNT_DISTINCT(source.ip),
        Esql.distinct_count_dst_ip = COUNT_DISTINCT(destination.ip),
        src_ip = VALUES(source.ip),
        dst_ip = VALUES(destination.ip),
        url_domain = VALUES(url.domain),
        url_path = VALUES(url.path) by message, event.category, event.outcome

// first time seen is within 10m of the rule execution time
| eval Esql.recent = DATE_DIFF("minute", Esql.first_time_seen, now())
| where Esql.recent <= 10 and Esql.alerts_count <= 5 and Esql.distinct_count_src_ip <= 2 and Esql.distinct_count_dst_ip <= 2

// move dynamic fields to ECS equivalent for rule exceptions
| eval source.ip = MV_FIRST(src_ip),
       destination.ip = MV_FIRST(dst_ip),
       url.domain = MV_FIRST(url_domain),
       url.path = MV_FIRST(url_path)

| keep message, event.category, event.outcome, Esql.*, source.ip, destination.ip, url.domain, url.path
```