The rule evaluates multiple VPN logon failures within a ten-minute window. The rule will generate an incident if there are more than three VPN logon failures from the same source IP address within a ten-minute window. Based on the VPN failure events received within a ten-minute window, there are two incidents generated:

One incident for source IP address 10.10.10.10, which has four VPN logon failures at 09:01, 09:02, 09:03, and 09:04.

One incident for source IP address 10.10.10.11, which has four VPN logon failures at 09:06, 09:07, 09:08, and 09:09.

The profile database contains CPU utilization values from day one. At midnight on the second day, the CPU utilization values from the daily database will be merged with the profile database using a weighted average formula:

New value = (Old value x Old weight) + (New value x New weight) / (Old weight + New weight)

The weight is determined by the number of days in each database. In this case, the profile database has one day of data and the daily database has one day of data, so the weight is equal for both databases. Therefore, the formula simplifies to:

New value = (Old value + New value) / 2

In the profile database, in the Hour of Day column where 9 is the value, the updated minimum, maximum, and average CPU utilization values are:

Min CPU Util = (32.31 + 32.31) / 2 = 32.31 Max CPU Util = (33.50 + 33.50) / 2 = 33.50 AVG CPU Util = (32.67 + 32.67) / 2 = 32.67

When a user is off-net, meaning they are not connected to a network where a FortiSIEM collector is reachable, then UEBA events will be cached locally by the agent if it cannot upload them to a FortiSIEM collector. The agent will store up to 100 MB of events in a local database file and try to upload them when it detects a network change or every five minutes.

Reconnaissance and Discovery are two Tactics in the MITRE ATT & CK framework. Tactics are the high-level objectives of an adversary, such as initial access, persistence, lateral movement, etc. Reconnaissance is the tactic of gathering information about a target before launching an attack. Discovery is the tactic of exploring a compromised system or network to find information or assets of interest. References:  Fortinet NSE 7 - Advanced Analytics 6.3 Exam Description , page 21

Collectors cannot be defined before the worker upload address is set on the supervisor because collectors receive the worker upload address during the registration process. The worker upload address is a list of IP addresses of worker nodes that can receive event data from collectors. The supervisor provides this list to collectors when they register with it, so that collectors can upload event data to any node in the list.

The collector processes are responsible for receiving, parsing, normalizing, correlating, and monitoring events from various sources. The collector processes are phParser, phRuleMaster, and phMonitorAgent.

The rule filters events with an event type that belong to the Domain Account Locked CMDB group and a reporting IP that belong to the Domain Controller applications group. This means that only events that have both criteria met will be processed by this rule. The event type and reporting IP are joined by an AND operator, which requires both conditions to be true.

The processes associated with Machine Learning/AI on FortiSIEM are phFortiInsightAI and phAnomaly. phFortiInsightAI is responsible for detecting anomalous user behavior using UEBA (User and Entity Behavior Analytics) techniques. phAnomaly is responsible for detecting anomalous network behavior using NTA (Network Traffic Analysis) techniques.

The mistake that the administrator made is that customer A and customer B have overlapping IP addresses. This will cause confusion and errors in event collection and correlation, as well as CMDB discovery and classification. To avoid this problem, each customer should have a unique IP address range or use NAT to translate their IP addresses.

FortiSIEM allows EPS bursting to handle event spikes without dropping events or violating the license agreement. EPS bursting means that FortiSIEM will let you burst up to five times the licensed EPS at any given time, provided it has accumulated enough unused EPS from previous time intervals.