WAF Logging

You can enable logging to get detailed information about traffic that is analyzed by your web ACL. Logged information includes the time that AWS WAF received a web request from your AWS resource, detailed information about the request, and details about the rules that the request matched.

You can send protection pack (web ACL) logs to

1. Amazon CloudWatch Logs log group
2. Amazon Simple Storage Service (Amazon S3) bucket
3. Amazon Data Firehose delivery stream

In addition to logs that you can enable for your protection packs (web ACLs), AWS also uses service logs of website or application traffic processed by AWS WAF to provide support for and protect the security of AWS customers and services.

Logging AWS WAF protection pack (web ACL) traffic - AWS WAF, AWS Firewall Manager, AWS Shield Advanced, and AWS Shield network security director

S3 Logging

To send your protection pack (web ACL) traffic logs to Amazon S3, you set up an Amazon S3 bucket from the same account as you use to manage the protection pack (web ACL), and you name the bucket starting with aws-waf-logs-. When you enable logging in AWS WAF, you provide the bucket name.

You can access and analyze your Amazon S3 logs using the Amazon Athena interactive query service. Athena makes it easy to analyze data directly in Amazon S3 using standard SQL. With a few actions in the AWS Management Console, you can point Athena at data stored in Amazon S3 and quickly begin using standard SQL to run ad-hoc queries and get results.

Log files from your protection pack (web ACL) are published to the Amazon S3 bucket at 5-minute intervals. Each log file contains log records for the traffic recorded in the previous 5 minutes.

The maximum file size for a log file is 75 MB. If the log file reaches the file size limit within the 5-minute period, the log stops adding records to it, publishes it to the Amazon S3 bucket, and then creates a new log file.

The log files are compressed. If you open the files using the Amazon S3 console, Amazon S3 decompresses the log records and displays them. If you download the log files, you must decompress them to view the records.

A single log file contains interleaved entries with multiple records. To see all the log files for a protection pack (web ACL), look for entries aggregated by the protection pack (web ACL) name, Region, and your account ID.

s3://aws-waf-logs-LOGGING-BUCKET-SUFFIX/KEY-NAME-PREFIX/AWSLogs/account-id/WAFLogs/Region/web-acl-name/YYYY/MM/dd/HH/mm/account-id_waflogs_Region_web-acl-name_timestamp_hash.log.gz

s3://aws-waf-logs-LOGGING-BUCKET-SUFFIX/AWSLogs/11111111111/WAFLogs/us-east-1/TEST-WEBACL/2021/10/28/19/50/11111111111_waflogs_us-east-1_TEST-WEBACL_20211028T1950Z_e0ca43b5.log.gz

Sending protection pack (web ACL) traffic logs to an Amazon Simple Storage Service bucket - AWS WAF, AWS Firewall Manager, AWS Shield Advanced, and AWS Shield network security director

On rare occasions, it's possible for AWS WAF log delivery to fall below 100%, with logs delivered on a best effort basis. The AWS WAF architecture prioritizes the security of your applications over all other considerations. In some situations, such as when logging flows experience traffic throttling, this can result in records being dropped. This shouldn't affect more than a few records. If you notice a number of missing log entries, contact the AWS Support Center.

In the logging configuration for your protection pack (web ACL), you can customize what AWS WAF sends to the logs.

Field redaction

You can redact the following fields from the log records for the rules that use the corresponding match settings: URI path, Query string, Single header, and HTTP method. Redacted fields appear as REDACTED in the logs. For example, if you redact the Query string field, in the logs, it will be listed as REDACTED for all rules that use the Query string match component setting. Redaction applies only to the request component that you specify for matching in the rule, so the redaction of the Single header component doesn't apply to rules that match on Headers. For a list of the log fields, see Log fields for protection pack (web ACL) traffic.

Log filtering

You can add filtering to specify which web requests are kept in the logs and which are dropped. You filter on the settings that AWS WAF applies during the web request evaluation. You can filter on the following settings:

• Fully qualified label – Fully qualified labels have a prefix, optional namespaces, and label name. The prefix identifies the rule group or protection pack (web ACL) context of the rule that added the label. For information about labels, see Web request labeling in AWS WAF.
• Rule action – You can filter on any normal rule action setting and also on the legacy EXCLUDED_AS_COUNT override option for rule group rules. For information about rule action settings, see Using rule actions in AWS WAF. For information about current and legacy rule action overrides for rule group rules, see Overriding rule group actions in AWS WAF.
  • The normal rule action filters apply to actions that are configured in rules and also to actions that are configured using the current option for overriding a rule group rule action.
  • The EXCLUDED_AS_COUNT log filter overlaps with the Count action log filter. EXCLUDED_AS_COUNT filters both the current and legacy options for overriding a rule group rule action to Count.

Finding your protection pack (web ACL) records - AWS WAF, AWS Firewall Manager, AWS Shield Advanced, and AWS Shield network security director