Log Intra Data Center Traffic That Matches the Intrazone Allow Rule

Data centers are a good place for attackers to hide because security often focuses on users and overlooks servers. Log east-west traffic between servers and look for anomalous behaviors that may indicate the presence of an attacker.
By default, all intrazone traffic (source and destination in the same zone) is allowed. After the firewall evaluates Security policy, it either allows traffic controlled by application whitelist rules, denies traffic controlled by block rules, or if intrazone traffic matches no rules, the firewall allows it by default. (The firewall blocks interzone traffic by default.) Because of the valuable nature of data center assets, the best practice is to monitor all traffic inside the data center between data center servers, including traffic allowed by the intrazone default allow rule.
To gain visibility into this traffic, enable logging on the intrazone-default rule when it applies to traffic within zones inside the data center. Logging this traffic gives you the opportunity to examine access that you have not explicitly allowed and which you may want to either explicitly allow by modifying a whitelist rule or explicitly block.
In Define the Initial Intra-Data-Center Traffic Security Policy, we used three example zones inside the data center: Web-Server-Tier-DC, App-Server-Tier-DC, and DB-Server-Tier-DC. In this example, we create a custom report to gather log information about data center intrazone traffic in these three internal data center zones.
  1. Select the intrazone-default row in the rulebase and click Override to enable editing the rule.
  2. Select the intrazone-default rule name to edit the rule.
  3. On the Actions tab, select Log at Session End and click OK.
  4. Create a custom report to monitor traffic that hits this rule for the internal data center zones.
    1. Select MonitorManage Custom Reports.
    2. Add a report and give it a descriptive Name. In this example, the name is Log Intrazone-Default Rule-DC.
    3. Set the Database to Traffic Summary.
    4. Select the Scheduled box.
    5. From Available Columns, add Application, Risk of App, Rule, and Threat to the Selected Columns list. If there are other types of information you want to monitor, select those as well.
    6. Set the desired Time Frame, Sort By, and Group By values. In this example, the selected values are Threats and App Category, respectively.
    7. Define the query to match traffic that matches the intrazone-default rule for the data center zones:
      (rule eq interzone-default) and ((zone eq Web-Server-Tier-DC) or (zone eq App-Server-Tier-DC) or (zone eq DB-Server-Tier-DC))
      The query filters for traffic that matches the interzone default rule and also matches any of the three internal data center zones that we defined. Because the default Selected Columns include zones, the report shows the zone for each session. In a real-world data center, you would probably have more zones and you would add each zone to the query. The resulting custom report settings look like this:
      custom-report-intrazone-inter-dc-traffic.png
    8. Commit the changes.

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