---
title: 'Mutelisting'
---

**Muting Findings for Intentional Configurations**

In some cases, certain AWS resources may be intentionally configured in a way that deviates from security best practices but serves a valid use case. Examples include:

An AWS S3 bucket open to the Internet, used for hosting a public website.

An AWS security group with an open port necessary for a specific application.

**Mutelist Option Behavior**

The Mutelist option works in combination with other filtering mechanisms and modifies the output in the following way when a finding is muted:

- JSON-OCSF: `status_id` is `Suppressed`.
- CSV: `muted` is `True`. The field `status` will keep the original status, `MANUAL`, `PASS` or `FAIL`, of the finding.

## How the Mutelist Works

The **Mutelist** uses **AND logic** to evaluate whether a finding should be muted. For a finding to be muted, **ALL** of the following conditions must match:

- **Account** matches (exact match or `*`)
- **Check** matches (exact match, regex pattern, or `*`)
- **Region** matches (exact match, regex pattern, or `*`)
- **Resource** matches (exact match, regex pattern, or `*`)
- **Tags** match (if specified)

If **any** of these criteria do not match, the finding is **not muted**.

### Tag Matching Logic

Tags have special matching behavior:

- **Multiple tags in the list = AND logic**: ALL tags must be present on the resource
  ```yaml
  Tags:
    - "environment=dev"
    - "team=backend"  # BOTH tags required
  ```

- **Regex alternation within a single tag = OR logic**: Use the pipe operator `|` for OR
  ```yaml
  Tags:
    - "environment=dev|environment=stg"  # Matches EITHER dev OR stg
  ```

- **Complex tag patterns**: Combine AND and OR using regex
  ```yaml
  Tags:
    - "team=backend"  # Required
    - "environment=dev|environment=stg"  # AND (dev OR stg)
  ```

<Note>
Remember that mutelist can be used with regular expressions.

</Note>
## Mutelist Specification

<Note>
- For Azure provider, the Account ID is the Subscription Name and the Region is the Location.
- For GCP provider, the Account ID is the Project ID and the Region is the Zone.
- For Kubernetes provider, the Account ID is the Cluster Name and the Region is the Namespace.

</Note>
The Mutelist file uses the [YAML](https://en.wikipedia.org/wiki/YAML) format with the following syntax:

```yaml
### Account, Check and/or Region can be * to apply for all the cases.
### Resources and tags are lists that can have either Regex or Keywords.
### Multiple tags in the list are "ANDed" together (ALL must match).
### Use regex alternation (|) within a single tag for "OR" logic (e.g., "env=dev|env=stg").
### For each check you can use Exceptions to unmute specific Accounts, Regions, Resources and/or Tags.
### All conditions (Account, Check, Region, Resource, Tags) are ANDed together.
###########################  MUTELIST EXAMPLE  ###########################
Mutelist:
  Accounts:
    "123456789012":
      Checks:
        "iam_user_hardware_mfa_enabled":
          Regions:
            - "us-east-1"
          Resources:
            - "user-1"           # Will mute user-1 in check iam_user_hardware_mfa_enabled
            - "user-2"           # Will mute user-2 in check iam_user_hardware_mfa_enabled
          Description: "Findings related with the check iam_user_hardware_mfa_enabled will be muted for us-east-1 region and user-1, user-2 resources"
        "ec2_*":
          Regions:
            - "*"
          Resources:
            - "*"                 # Will mute every EC2 check in every account and region
        "*":
          Regions:
            - "*"
          Resources:
            - "test"
          Tags:
            - "test=test"         # Will mute every resource containing the string "test" and the tags 'test=test' and
            - "project=test|project=stage" # either of ('project=test' OR project=stage) in account 123456789012 and every region
        "*":
            Regions:
              - "*"
            Resources:
              - "test"
            Tags:
              - "test=test"
              - "project=test"    # This will mute every resource containing the string "test" and BOTH tags at the same time.
        "*":
            Regions:
              - "*"
            Resources:
              - "test"
            Tags:                 # This will mute every resource containing the string "test" and the ones that contain EITHER the `test=test` OR `project=test` OR `project=dev`
              - "test=test|project=(test|dev)"
        "*":
            Regions:
              - "*"
            Resources:
              - "test"
            Tags:
              - "test=test"       # This will mute every resource containing the string "test" and the tags `test=test` and either `project=test` OR `project=stage` in every account and region.
              - "project=test|project=stage"

    "*":
      Checks:
        "s3_bucket_object_versioning":
          Regions:
            - "eu-west-1"
            - "us-east-1"
          Resources:
            - "ci-logs"           # Will mute bucket "ci-logs" AND ALSO bucket "ci-logs-replica" in specified check and regions
            - "logs"              # Will mute EVERY BUCKET containing the string "logs" in specified check and regions
            - ".+-logs"           # Will mute all buckets containing the terms ci-logs, qa-logs, etc. in specified check and regions
        "ecs_task_definitions_no_environment_secrets":
          Regions:
            - "*"
          Resources:
            - "*"
          Exceptions:
            Accounts:
              - "0123456789012"
            Regions:
              - "eu-west-1"
              - "eu-south-2"        # Will mute every resource in check ecs_task_definitions_no_environment_secrets except the ones in account 0123456789012 located in eu-south-2 or eu-west-1
        "*":
          Regions:
            - "*"
          Resources:
            - "*"
          Tags:
            - "environment=dev"    # Will mute every resource containing the tag 'environment=dev' in every account and region

    "123456789012":
      Checks:
        "*":
          Regions:
            - "*"
          Resources:
            - "*"
          Exceptions:
            Resources:
              - "test"
            Tags:
              - "environment=prod"   # Will mute every resource except in account 123456789012 except the ones containing the string "test" and tag environment=prod

    "*":
      Checks:
        "ec2_*":
          Regions:
            - "*"
          Resources:
            - "test-resource" # Will mute the resource "test-resource" in all accounts and regions for whatever check from the EC2 service
```


### Account, Check, Region, Resource, and Tag

| Field| Description| Logic
|----------|----------|----------
| `account_id`| Use `*` to apply the mutelist to all accounts. Supports exact match or wildcard.| `AND` (with other fields)
| `check_name`| The name of the Prowler check. Use `*` to apply the mutelist to all checks, or `service_*` to apply it to all service's checks. Supports regex patterns.| `AND` (with other fields)
| `region`| The region identifier. Use `*` to apply the mutelist to all regions. Supports regex patterns.| `AND` (with other fields)
| `resource`| The resource identifier. Use `*` to apply the mutelist to all resources. Supports regex patterns.| `AND` (with other fields)
| `tags`| List of tag patterns in `key=value` format. **Multiple tags = AND** (all must match). **Regex alternation within single tag = OR** (use `tag1\|tag2`).| `AND` between tags, `OR` within regex

### Description

This field can be used to add information or some hints for the Mutelist rule.

## How to Use the Mutelist

To use the Mutelist, you need to specify the path to the Mutelist YAML file using the `-w` or `--mutelist-file` option when running Prowler:

```
prowler <provider> -w mutelist.yaml
```

Replace `<provider>` with the appropriate provider name.

## Considerations

- The Mutelist can be used in combination with other Prowler options, such as the `--service` or `--checks` option, to further customize the scanning process.
- Make sure to review and update the Mutelist regularly to ensure it reflects the desired exclusions and remains up to date with your infrastructure.

## Current Limitations and Workarounds

### Limitation: No OR Logic Between Different Rule Sets

The current Mutelist schema **does not support OR logic** between different condition sets. Each check can have only **one rule object**, and all conditions are **ANDed** together.

**Example of unsupported scenario:**
```yaml
# ❌ INVALID: Cannot have multiple rule blocks for the same check
Accounts:
  "*":
    Checks:
      "*":  # Rule 1
        Regions: ["eu-west-1", "us-west-2"]
        Resources: ["*"]
      "*":  # Rule 2 - This will OVERWRITE Rule 1 (YAML duplicate key)
        Regions: ["us-east-1"]
        Tags: ["environment=dev"]
```

**Workaround: Use multiple scans with different mutelists**

For complex scenarios requiring OR logic, run separate scans:

```bash
# Scan 1: Mute findings in non-critical regions
prowler aws --mutelist-file mutelist_noncritical.yaml

# Scan 2: Mute dev/stg in critical regions
prowler aws --mutelist-file mutelist_critical.yaml --regions us-east-1,sa-east-1
```

Then merge the outputs in your reporting pipeline.

### Limitation: Cannot Negate Regions

You cannot express "all regions **except** X and Y". You must explicitly list all regions you want to mute.

**Workaround:**
```yaml
# Must enumerate all unwanted regions
Accounts:
  "*":
    Checks:
      "*":
        Regions:
          - "af-south-1"
          - "ap-east-1"
          # ... list all regions EXCEPT the ones you want to monitor
        Resources: ["*"]
```

### Best Practices

1. **Use regex patterns for flexibility**: Instead of listing multiple resources, use regex patterns like `"dev-.*"` or `"test-instance-[0-9]+"`

2. **Combine tag OR logic with regex**: Use `"environment=dev|environment=stg|environment=test"` instead of multiple tag entries

3. **Be specific with exceptions**: Use the `Exceptions` field to unmute specific resources within a broader muting rule

4. **Test your mutelist**: Run Prowler with `--output-modes json` and verify that the expected findings are muted

## AWS Mutelist

### Muting specific AWS regions

If you want to mute failed findings only in specific regions, create a file with the following syntax and run it with `prowler aws -w mutelist.yaml`:

    Mutelist:
      Accounts:
      "*":
        Checks:
          "*":
            Regions:
              - "ap-southeast-1"
              - "ap-southeast-2"
            Resources:
              - "*"
            Description: "Description related with the muted findings for the check"

### Default Mutelist

For the AWS Provider, Prowler is executed with a default AWS Mutelist with the AWS Resources that should be muted such as all resources created by AWS Control Tower when setting up a landing zone that can be found in [AWS Documentation](https://docs.aws.amazon.com/controltower/latest/userguide/shared-account-resources.html). You can see this Mutelist file in [`prowler/config/aws_mutelist.yaml`](https://github.com/prowler-cloud/prowler/blob/master/prowler/config/aws_mutelist.yaml).

### Supported Mutelist Locations

The mutelisting flag supports the following AWS locations when using the AWS Provider:

#### AWS S3 URI

You will need to pass the S3 URI where your Mutelist YAML file was uploaded to your bucket:

```
prowler aws -w s3://<bucket>/<prefix>/mutelist.yaml
```

<Note>
Make sure that the used AWS credentials have `s3:GetObject` permissions in the S3 path where the mutelist file is located.

</Note>
#### AWS DynamoDB Table ARN

You will need to pass the DynamoDB Mutelist Table ARN:

```
prowler aws -w arn:aws:dynamodb:<region_name>:<account_id>:table/<table_name>
```

The DynamoDB Table must have the following String keys:

  <img src="/images/cli/mutelist-keys.png" />

The Mutelist Table must have the following columns:

  - Accounts (String): This field can contain either an Account ID or an `*` (which applies to all the accounts that use this table as an mutelist).

  - Checks (String): This field can contain either a Prowler Check Name or an `*` (which applies to all the scanned checks).

  - Regions (List): This field contains a list of regions where this mutelist rule is applied (it can also contains an `*` to apply all scanned regions).

  - Resources (List): This field contains a list of regular expressions (regex) that applies to the resources that are wanted to be muted.

  - Tags (List): -Optional- This field contains a list of tuples in the form of 'key=value' that applies to the resources tags that are wanted to be muted.

  - Exceptions (Map): -Optional- This field contains a map of lists of accounts/regions/resources/tags that are wanted to be excepted in the mutelist.

The following example will mute all resources in all accounts for the EC2 checks in the regions `eu-west-1` and `us-east-1` with the tags `environment=dev` and `environment=prod`, except the resources containing the string `test` in the account `012345678912` and region `eu-west-1` with the tag `environment=prod`:

<img src="/images/cli/mutelist-row.png" />

<Note>
Make sure that the used AWS credentials have `dynamodb:PartiQLSelect` permissions in the table.

</Note>
#### AWS Lambda ARN

You will need to pass the AWS Lambda Function ARN:

```
prowler aws -w arn:aws:lambda:REGION:ACCOUNT_ID:function:FUNCTION_NAME
```

Make sure that the credentials that Prowler uses can invoke the Lambda Function:

```
- PolicyName: GetMuteList
  PolicyDocument:
    Version: '2012-10-17'
    Statement:
      - Action: 'lambda:InvokeFunction'
        Effect: Allow
        Resource: arn:aws:lambda:REGION:ACCOUNT_ID:function:FUNCTION_NAME
```

The Lambda Function can then generate an Mutelist dynamically. Here is the code an example Python Lambda Function that generates an Mutelist:

```
def handler(event, context):
  checks = {}
  checks["vpc_flow_logs_enabled"] = { "Regions": [ "*" ], "Resources": [ "" ], Optional("Tags"): [ "key:value" ] }

  al = { "Mutelist": { "Accounts": { "*": { "Checks": checks } } } }
  return al
```
