Table of Contents

Configure Flow Logs

Prisma Cloud ingests the VPC flow logs from Amazon S3 buckets stored in a logging account and makes it available for network policy alerting and visualization. After onboarding your AWS account, you need to onboard the logging account which has the S3 bucket storing VPC flow logs for the monitored account. The default retention period of flow logs is 30 days after which they are purged. You can query flow logs data for the last 30 days. CloudWatch is the default selection to ingest flow logs and does not require additional configuration.
When creating S3 flow logs on the AWS console, make sure to partition your flow logs for
Every 1 hour (60 minutes)
. The hourly (60 minutes) partition provides better ingestion performance than the 24 hours partition. Selecting additional fields on the AWS console that are used in the Internet exposure calculation in network policies address the false positives for those network policies.
  1. On your AWS console, create a flow log with the following specifications.
    1. The new flow logs format requires all connection direction related fields. Here’s a sample format:
    2. Select all
      instead of manually selecting each field.
      Or you can choose custom format and select the following required fields:
      • account-id
      • action
      • interface-id
      • srcaddr
      • dstaddr
      • srcport
      • dstport
      • protocol
      • packets
      • bytes
      • start
      • end
      • log-status
      • region
      • version
      • tcp-flags
      • flow-direction
      • traffic-path
      • vpc-id
      • subnet-id
      • instance-id
      • pkt-srcaddr
      • pkt-dstaddr
      • pkt-src-aws-service
      • pkt-dst-aws-service
    3. Set
      Partition logs by time
      Every 1 hour (60 minutes)
    4. Set
      Log file format
      . Prisma Cloud supports ingestion of only text format files.
  2. You are not required to change anything on Prisma Cloud as long as the S3 bucket does not change.

Onboarded Accounts that Use S3

For your previously onboarded AWS accounts that are using S3 with 24 hours partition, you can now select hourly partition. Prisma Cloud checks whether flow logs have all the necessary permissions required for hourly partition (it does not check for the fields).
  1. After you Onboard Your AWS Account, select
    Cloud Accounts
  2. Click the
    ( ) icon next to the AWS account for which you want to configure the logging account and buckets to fetch flow logs from S3.
  3. Click
    Threat Detection
  4. Select
    Flow Logs
  5. Click
    Configure S3
  6. Configure Logging Account
    1. Click
      Add Logging Account
      or select from the logging accounts displayed (if you have previously set up logging accounts).
    2. Click
    3. Enter an
      Account ID
      Account Name
      , and
      Role Name
      and click
      . By default, the role name is
      , which you can customize.
      All the configured Logging Accounts are displayed. You can select one of these Logging Accounts which contains the S3 bucket to which the VPC flow logs are being sent for the respective monitored account. Or you can
      a new Logging Account as described in the step above.
  7. Configure Buckets
    1. Enter a
      Bucket Name
      and the
      Bucket Region
      that you have configured as destination for flow logs on the AWS Logging Account VPC Console. The
      Bucket Path Prefix
      (comma separated list) and
      Key ARN
      are optional. If you have any specific path (Bucket Path) prefix for flow logs and configured bucket encryption (Key ARN), you can enter those values.
      If you’ve enabled hourly partitions, the files are published to the following location: bucket-and-optional-prefix/AWSLogs/account_id/vpcflowlogs/region/year/month/day/hour/
      In AWS, the bucket-and-optional-prefix is added to the S3 bucket ARN as a folder in the flow log settings page. Make sure you add the same bucket-and-optional-prefix in the prefix section in Prisma Cloud.
    2. Add
      multiple buckets used for logging.
  8. Click
  9. Follow the steps displayed on
    Logging Account Template
    1. Enter the
      Role ARN
    2. Click
      You can proceed further only if the validation is successful and you see a green
      The CFT template is deployed on the Logging Account through your AWS Management Console.
  10. Click
  11. Configure S3 Flowlogs
    1. Select all the applicable
      Logging Buckets
      that Prisma Cloud can access and from which it can ingest flow logs.
    2. After selecting the Logging Buckets, click
      to make sure Prisma Cloud has all basic required permissions and access.
      If all the required permissions are present, a green
      checkmark displays. If not, an error message displays.
      If you want to configure a different logging account and buckets, click the
  12. Click
    You can save your settings, regardless of the validation status.
    For accounts that are using CloudWatch and now you want to upgrade to S3, the
    Enable Hourly Partition
    checkbox is enabled (grayed out) by default to ensure it is using hourly partition.

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