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Event Information

  • The DeleteRegexPatternSet event in AWS WAF refers to the action of deleting a regex pattern set within the Web Application Firewall (WAF) service.
  • Regex pattern sets in AWS WAF are used to define regular expressions that can be matched against the content of web requests. These patterns are typically used to identify and block malicious or unwanted traffic.
  • When the DeleteRegexPatternSet event occurs, it means that a specific regex pattern set has been removed from the WAF configuration, and any rules or conditions associated with that pattern set will no longer be enforced.

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Examples

  1. Inadvertent deletion: If the DeleteRegexPatternSet operation is misconfigured or executed without proper authorization, it can lead to the inadvertent deletion of a regex pattern set. This can impact the security of the WAF (Web Application Firewall) as the deleted patterns will no longer be enforced, potentially leaving the application vulnerable to attacks.

  2. Loss of protection: Deleting a regex pattern set that is actively used by the WAF rules can result in the loss of protection against specific types of attacks. For example, if a regex pattern set containing rules to block SQL injection attempts is deleted, the WAF will no longer be able to detect and block such attacks, increasing the risk to the application’s security.

  3. Configuration errors: If the DeleteRegexPatternSet operation is performed incorrectly, it can lead to the deletion of the wrong pattern set. This can result in misconfiguration of the WAF rules, potentially allowing malicious traffic to bypass the intended protections. It is important to double-check the target pattern set before executing the deletion to avoid such errors.

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Remediation

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Using Console

  1. Identify the specific AWS WAF rule that needs to be remediated based on the examples provided.

    • Log in to the AWS Management Console.
    • Navigate to the AWS WAF service.
    • Select the appropriate WebACL that contains the rule that needs to be remediated.

  2. Modify the AWS WAF rule to address the identified issue.

    • Within the selected WebACL, locate the rule that needs to be remediated.
    • Click on the rule to access its configuration settings.
    • Adjust the rule’s conditions, filters, or actions as necessary to address the issue.
    • Save the changes made to the rule.

  3. Test and monitor the remediated AWS WAF rule.

    • Deploy the updated WebACL to the appropriate AWS resources (e.g., CloudFront distribution, Application Load Balancer).
    • Monitor the traffic and logs to ensure that the remediated rule is functioning as expected.
    • Continuously monitor and analyze the logs and metrics to identify any potential issues or anomalies.
    • Make further adjustments to the rule if necessary based on the observed behavior.

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Using CLI

  1. To remediate a specific rule in AWS WAF using AWS CLI, you can use the update-rule command. For example, if you want to update the rule with the rule ID “12345678-1234-1234-1234-123456789012” in a WebACL named “MyWebACL”, you can use the following command:
aws wafv2 update-rule --name MyWebACL --scope REGIONAL --id 12345678-1234-1234-1234-123456789012 --action ALLOW --override-action NONE

This command updates the specified rule to allow the traffic and removes any overriding actions.

  1. To remediate a rate-based rule in AWS WAF using AWS CLI, you can use the update-rate-based-rule command. For example, if you want to update the rate-based rule with the rule ID “12345678-1234-1234-1234-123456789012” in a WebACL named “MyWebACL”, you can use the following command:
aws wafv2 update-rate-based-rule --name MyWebACL --scope REGIONAL --id 12345678-1234-1234-1234-123456789012 --rate-key IP --rate-limit 1000

This command updates the specified rate-based rule to limit the requests per IP to 1000.

  1. To remediate a managed rule group in AWS WAF using AWS CLI, you can use the update-managed-rule-set-version command. For example, if you want to update the managed rule group with the ARN “arn:aws:wafv2:us-west-2:123456789012:managed-rule-set/aws-managed/gbqj2j5k5k-owasp-top-10” to the latest available version, you can use the following command:
aws wafv2 update-managed-rule-set-version --name gbqj2j5k5k-owasp-top-10 --scope REGIONAL --vendor-name aws-managed --managed-rule-set-id gbqj2j5k5k-owasp-top-10 --version-name LATEST

This command updates the specified managed rule group to the latest available version.

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Using Python

  1. Example 1: Blocking IP addresses with AWS WAF using Python:
    • Use the AWS SDK for Python (Boto3) to interact with AWS WAF.
    • Write a Python script to retrieve the IP addresses that need to be blocked.
    • Use the create_ip_set method to create an IP set in AWS WAF.
    • Use the update_ip_set method to add the retrieved IP addresses to the IP set.
    • Use the update_web_acl method to associate the IP set with the desired web ACL.
import boto3

# Create AWS WAF client
waf_client = boto3.client('waf')

# Retrieve IP addresses to block
ip_addresses = ['192.0.2.1', '203.0.113.2']

# Create IP set
response = waf_client.create_ip_set(
    Name='BlockedIPSet',
    ChangeToken='CHANGE_TOKEN'
)

# Add IP addresses to IP set
response = waf_client.update_ip_set(
    IPSetId='IP_SET_ID',
    ChangeToken='CHANGE_TOKEN',
    Updates=[
        {
            'Action': 'INSERT',
            'IPSetDescriptor': {
                'Type': 'IPV4',
                'Value': ip_address
            }
        }
        for ip_address in ip_addresses
    ]
)

# Associate IP set with web ACL
response = waf_client.update_web_acl(
    WebACLId='WEB_ACL_ID',
    ChangeToken='CHANGE_TOKEN',
    Updates=[
        {
            'Action': 'INSERT',
            'ActivatedRule': {
                'Priority': 1,
                'RuleId': 'BLOCK_RULE_ID',
                'Action': {
                    'Type': 'BLOCK'
                }
            }
        }
    ]
)
  1. Example 2: Enabling AWS WAF rate-based rules using Python:
    • Use the AWS SDK for Python (Boto3) to interact with AWS WAF.
    • Write a Python script to enable rate-based rules for a specific web ACL.
    • Use the create_rate_based_rule method to create a rate-based rule.
    • Use the update_web_acl method to associate the rate-based rule with the desired web ACL.
import boto3

# Create AWS WAF client
waf_client = boto3.client('waf')

# Create rate-based rule
response = waf_client.create_rate_based_rule(
    Name='RateBasedRule',
    MetricName='RateBasedRule',
    RateKey='IP',
    RateLimit=1000,
    ChangeToken='CHANGE_TOKEN'
)

# Associate rate-based rule with web ACL
response = waf_client.update_web_acl(
    WebACLId='WEB_ACL_ID',
    ChangeToken='CHANGE_TOKEN',
    Updates=[
        {
            'Action': 'INSERT',
            'ActivatedRule': {
                'Priority': 1,
                'RuleId': 'RATE_BASED_RULE_ID',
                'Action': {
                    'Type': 'BLOCK'
                }
            }
        }
    ]
)
  1. Example 3: Creating AWS WAF rules to block SQL injection attacks using Python:
    • Use the AWS SDK for Python (Boto3) to interact with AWS WAF.
    • Write a Python script to create AWS WAF rules to block SQL injection attacks.
    • Use the create_rule method to create a rule for SQL injection attacks.
    • Use the update_web_acl method to associate the rule with the desired web ACL.
import boto3

# Create AWS WAF client
waf_client = boto3.client('waf')

# Create rule for SQL injection attacks
response = waf_client.create_rule(
    Name='SQLInjectionRule',
    MetricName='SQLInjectionRule',
    ChangeToken='CHANGE_TOKEN',
    Predicates=[
        {
            'DataId': 'SQL_INJECTION_DATA_ID',
            'Negated': False,
            'Type': 'SQLi'
        }
    ]
)

# Associate rule with web ACL
response = waf_client.update_web_acl(
    WebACLId='WEB_ACL_ID',
    ChangeToken='CHANGE_TOKEN',
    Updates=[
        {
            'Action': 'INSERT',
            'ActivatedRule': {
                'Priority': 1,
                'RuleId': 'SQL_INJECTION_RULE_ID',
                'Action': {
                    'Type': 'BLOCK'
                }
            }
        }
    ]
)