Security logs are one of the most important components of any security program. They provide insight into how well your security program is working, and they serve as a valuable source of intelligence for incident response. However, they are not perfect; they can contain false positives and false negatives. As a result, they need to be reviewed regularly to ensure they are providing accurate information.
There are two main reasons why security log reviews are necessary. First, they allow you to identify problems before they become serious incidents. Second, they allow you to determine whether your current security measures are effective.
When reviewing logs, look for three things:
1. Incidents – These are events that indicate something has gone wrong. For example, a firewall blocking access to a website, or a virus scanning software alerting you to a malware infection.
2. False Positives – These are alerts that don’t represent anything actually happening. For example, a virus scanner warning you about a file that was downloaded from the Internet without any infection identified.
3. False Negatives – These are alerts that do represent something actually happening, but were missed because of a flaw in the system. For example, a server being accessed remotely, but no alarms raised.
Reviewing logs every day is recommended. If you review logs daily, you will catch issues sooner and prevent them from becoming major incidents. This should be done on a rotating basis by the security team to prevent fatigue from diminishing the quality of the work, or via automated methods to reduce fatigue.
Peer reviewing logs weekly is also recommended. It allows you to spot trends and anomalies that might otherwise go unnoticed by a single reviewer. It also gives a second set of eyes on the logs, and helps guard against fatigue or bias-based errors.
Finally, aggregated trend-based monthly reviews are recommended. This gives you a chance to look back and see if there have been any changes to your environment that could affect your security posture or represent anomalies. This is a good place to review items like logged events per day, per system, trends on specific log events and the like. Anomalies should be investigated. Often times, this level of log review is great for spotting changes to the environment or threat intelligence.
If you want to learn more about how to conduct log reviews effectively, reach out to us at [email protected]. We’re happy to help!
