A critical part of any security architecture is logging and alerting. It wouldn't do much good to have all these defenses in place, if we have no idea if they're working or not. We need visibility into the security systems in place to see what kind of traffic they're seeing. We also need to have that visibility into the logs of all of our infrastructure devices and equipment that we manage. But it's not enough to just have logs, we also need ways to safeguard logs and make them easy to analyze and review. If there is a dedicated security team at your company, they would be performing this analysis. But at a smaller company, this responsibility would likely fall to the IT team. So, let's make sure you're prepared with the skills you might need for incident investigation. Many investigative techniques can also be applied to troubleshooting. All systems and services running on hosts will create logs of some kind, with different levels of detail. It depends on what it's logging, and what events it's configured to log. So, an authentication server we'd log every authentication attempt, whether it's successful or not. A firewall would log traffic that matches rules with details like source and destination addresses, and ports being used. All this logged information gives us details about the traffic and activity that's happening on our network and systems. This can be used to detect compromise or attempts to attack the system. When there are a large number of systems located around your network, each with their own log format, it can be challenging to make meaningful sense of all this data. This is where security information and event management systems or SIEMS come in. A SIEM can be thought of as a centralized log server. It has some extra analysis features too. In the system administration and IT infrastructure course of this program, you learn ways that centralized logging can help you administer multiple machines at once. You can think of SIEM as a form of centralized logging for security administration purposes. A SIEM system gets logs from a bunch of other systems. It consolidates the logs from all different places and places it in one centralized location. This makes handling logs a lot easier. As an IT support specialist, an important step you'll take in logs analysis is normalization. This is the process of taking log data in different formats and converting it into a standardized format that's consistent with a defined log structure. As an IT support specialist, you might configure normalization for your log sources. For example, log entries from our firewall may have a timestamp using a year, month, and day format, while logs from our client machines may use day, month, year format. To normalize this data, you choose one standard date format, then you define what the fields are for the log types that need to be converted. When logs are received from these machines, the log entries are converted into the standard that we defined, and stored by the logging server. This lets you analyze and compare log data between different log types and systems in a much easier fashion. So what type of information should you be logging? Well, that's a great question. If you log too much info, it's difficult to analyze a data and find useful information. Plus, storage requirements for saving logs become expensive very quickly. But if you log too little, then the information won't provide any useful insights into your systems and network. Finding that middle ground can be difficult. It will vary depending on the unique characteristics of the systems being monitored, and the type of activity on the network. No matter what events are logged, all of them should have information that will help understand what happened and reconstruct the events. There are lots of important fields to capture in log entries like timestamp, the event or error code, the service or application being logged, the user or system account associated with the event, and the devices involved in the event. Timestamps are super important to understanding when an event occurred. Fields like source and destination addresses will tell us who was talking to who. For application logs, you can grab useful information from the logged in user associated with the event, and from what client they used. On top of the analysis assistance it provides, a centralized live server also has security benefits. By maintaining logs on a dedicated system, it's easier to secure the system from attack. Logs are usually targeted by attackers after a breach, so that they can cover their tracks. By having critical systems send logs to remote logging server that's locked down, the details of a breach should still be logged. A forensics team will be able to reconstruct the events that led to the compromise. Once we have logging configured and the relevant events recorded on a centralized log server, what do we do with all the data? Well, analyzing log details depends on what you're trying to achieve. Typically, when you look at aggregated logs as an IT support specialist, you should pay attention to patterns and connections between traffic. So, if you're seeing a large percentage of Windows hosts, all connecting to specific address outside your network, that might be worth investigating. It could signal a malware infection. Once logs are centralized and standardized, you can write automated alerting based on rules. Maybe you'll want to find an alert rule for repeated unsuccessful attempts to authenticate to a critical authentication server. Lots of SIEMS solutions also offer handing dashboards to help analysts visualize this data. Having data in a visual format can potentially provide more insight. You can also write some of your own monitoring and alert systems. Now, it doesn't matter if you're using a SIEM solution or writing your own, it can be useful to break down things like commonly used protocols in the network, quickly see the top talkers in the network, interview reported errors over time to reveal patterns. Speaking of top talkers, I have just one more thing to call out. But we'll take a break before the next video. Another important component to logging to keep in mind as an IT support specialist, is retention. Your log storage needs will vary based on the amount of systems being logged, the amount of detail logs, and the rate at which logs are created. How long you want or need to keep logs around will also really influence the storage requirements for a log server. Some examples of logging servers and SIEMS solutions are the open source rsylog, Splunk Enterprise Security, IBM Security Qradar, and RSA Security analytics. You can learn more about these solutions in the supplementary readings of this lesson. Okay. Breaktime. I'll see you at the top of the next video on anti-malware protection.