Rate limiting

In a carding attack, an attacker tries to determine which credit card numbers are valid, usually in batches of thousands. Attackers can use similar techniques to brute force missing details, such as the expiration date. Adobe Commerce merchants can be targeted by this attack type through their shops and integrations with 3rd-party payment gateways.

As of Adobe Commerce 2.4.7, you can configure rate limiting for the payment information transmitted using REST and GraphQL. This added layer of protection allows merchants to prevent and decrease the volume of carding attacks that test many credit card numbers at once.

The rate limiting functionality affects the following entry points:

REST:

<base_url>/rest/V1/<store_code>/guest-carts/<cart_id>/payment-information
<base_url>/rest/V1/<store_code>/guest-carts/<cart_id>/order
<base_url>/rest/V1/<store_code>/carts/mine/payment-information
<base_url>/rest/V1/<store_code>/carts/mine/order

GraphQL:

<base_url>/graphql

InstantPurchase module:

magento/module-instant-purchase

Setting up rate limiting has two discrete steps:

Add a configuration that connects to the service where the request logs will be stored. By default, the connection is configured for a Redis server. Most merchants must configure a cloud or local installation of Redis to implement the rate limiting feature. However, merchants who have instances hosted on Amazon EC2 use an AWS ElastiCache instead of a cloud or local Redis instance.
Note: The data, including request time and identifier, is temporarily stored in Redis. Registered users are identified by their user ID. Non-registered users are identified by their external IP address.
Configure Commerce to set restrictions on guest users and authenticated customers. This step is the same for all merchants.

Set the Redis service connection (most merchants)

The Configure Redis topic in the Commerce Configuration Guide describes basic installation and configuration information.

Commerce provides command-line options to configure the connection to the backpressure logger. Although you can configure the backpressure logger by editing the <Commerce-install-dir>/app/etc/env.php file, using the command line is the recommended method, especially for initial configurations. The command line provides validation, ensuring the configuration is syntactically correct.

By default, the connection is configured for a Redis server. Use the following bin/magento setup:config:set commands to configure the Redis service connection:

Command line parameter	Value	Description	Default
`--backpressure-logger`	`redis`	Specifies the backpressure logger handler	This value must be set to `redis`.
`--backpressure-logger-id-prefix`	String	ID prefix for keys	None
`--backpressure-logger-redis-db`	Database number	Required if you use Redis for both the default and full-page cache. You must specify the database number of one of the caches; the other cache uses 0 by default. Important: If you use Redis for more than one type of caching, the database numbers must be different. It is recommended that you assign the default caching database number to 0, the page-caching database number to 1, and the session storage database number to 2. And as a result, the number of the database for storing the backpressure log is 3.	`3`
`--backpressure-logger-redis-password`	Password	Configuring a Redis password enables one of its built-in security features: the `auth` command, which requires clients to authenticate to access the database. The password is configured directly in Redis' configuration file: `/etc/redis/redis.conf`	None
`--backpressure-logger-redis-persistent`	String	Unique string to enable persistent connections	None
`--backpressure-logger-redis-port`	Port	Redis server listen port	`6379`
`--backpressure-logger-redis-server`	Server	Fully qualified hostname, IP address, or an absolute path to a UNIX socket. The default value of 127.0.0.1 indicates Redis is installed on the Commerce server.	`127.0.0.1`
`--backpressure-logger-redis-timeout`	Timeout	Redis server timeout, in seconds	2.5
`--backpressure-logger-redis-user`	User ID	Redis server user	None

The following example creates a new connection to a Redis server with the following properties:

Host: 195.34.23.5
Port: 9345
Password: s0M3StR0NgP@SsW0Rd
User: SomeUser

$ bin/magento setup:config:set \
    --backpressure-logger=redis \
    --backpressure-logger-redis-server=195.34.23.5 \
    --backpressure-logger-redis-port=9345 \
    --backpressure-logger-redis-timeout=1 \
    --backpressure-logger-redis-persistent=persistent \
    --backpressure-logger-redis-db=3 \
    --backpressure-logger-redis-password=s0M3StR0NgP@SsW0Rd\
    --backpressure-logger-redis-user=SomeUser \
    --backpressure-logger-id-prefix=some_pref
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$ bin/magento setup:config:set \
    --backpressure-logger=redis \
    --backpressure-logger-redis-server=195.34.23.5 \
    --backpressure-logger-redis-port=9345 \
    --backpressure-logger-redis-timeout=1 \
    --backpressure-logger-redis-persistent=persistent \
    --backpressure-logger-redis-db=3 \
    --backpressure-logger-redis-password=s0M3StR0NgP@SsW0Rd\
    --backpressure-logger-redis-user=SomeUser \
    --backpressure-logger-id-prefix=some_pref

After the command is executed, the following configuration is added to the app/etc/env.php file.

[
//...
    'backpressure' => [
        'logger' => [
            'type' => 'redis',
            'options' => [
                'server' => '195.34.23.5',
                'port' => 9345,
                'timeout' => 1,
                'persistent' => 'persistent',
                'db' => '3',
                'password' => 's0meStr0ngPassw0rd',
                'user' => 'SomeUser'
            ],
            'id-prefix' => 'some_pref'
        ]
    ]
//...
];
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[
//...
    'backpressure' => [
        'logger' => [
            'type' => 'redis',
            'options' => [
                'server' => '195.34.23.5',
                'port' => 9345,
                'timeout' => 1,
                'persistent' => 'persistent',
                'db' => '3',
                'password' => 's0meStr0ngPassw0rd',
                'user' => 'SomeUser'
            ],
            'id-prefix' => 'some_pref'
        ]
    ]
//...
];

Continue to Configure rate limiting

Use AWS ElastiCache with your EC2 instance

As of Commerce 2.4.3, instances hosted on Amazon EC2 can use an AWS ElastiCache in place of a local Redis instance.

This section applies to Commerce instances running on Amazon EC2 VPCs. It does not work for standard cloud or on-premises installations.

Configure a Redis cluster

After setting up a Redis cluster on AWS, configure the EC2 instance to use the ElastiCache.

Create an ElastiCache Cluster in the same region and VPC of the EC2 instance.

Verify the connection.

Open an SSH connection to your EC2 instance.

On the EC2 instance, install the Redis client:

sudo apt-get install redis
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sudo apt-get install redis

Add an inbound rule to the EC2 security group: Type - Custom TCP, port - 6379, Source - 0.0.0.0/0
Add an inbound rule to the ElastiCache Cluster security group: Type - Custom TCP, port - 6379, Source - 0.0.0.0/0

Connect to the Redis CLI:

redis-cli -h <ElastiCache Primary Endpoint host> -p <ElastiCache Primary Endpoint port>
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redis-cli -h <ElastiCache Primary Endpoint host> -p <ElastiCache Primary Endpoint port>

Configure Commerce to use the cluster

Run setup commands to specify the Redis endpoints. To configure Commerce for the backpressure logger connection:

bin/magento setup:config:set --backpressure-logger=redis --backpressure-logger-redis-server=<ElastiCache Primary Endpoint host> --backpressure-logger-redis-port=<ElastiCache Primary Endpoint port> --backpressure-logger-redis-db=3
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bin/magento setup:config:set --backpressure-logger=redis --backpressure-logger-redis-server=<ElastiCache Primary Endpoint host> --backpressure-logger-redis-port=<ElastiCache Primary Endpoint port> --backpressure-logger-redis-db=3

Configure rate limiting

After the Redis server connection has been configured, you can run several bin/magento config:set commands that define how rate limiting is implemented for guest users and authenticated customers. Rate limiting is disabled by default.

Parameter	Description
sales/backpressure/enabled	Enable rate limiting for placing orders.
sales/backpressure/disabled	Disable the rate limiting feature.
sales/backpressure/guest_limit	Requests limit per guest.
sales/backpressure/limit	Requests limit per authenticated customer.
sales/backpressure/period	The number of seconds to wait until resetting the counter.

You can also enable and configure rate limiting from the Admin by selecting Stores > Configuration > Sales > Sales > Rate Limiting.

Rate limiting section

Use the following commands to enable and configure rate limiting:

Enable (1) or disable (0) rate limiting for placing orders:

$ bin/magento config:set sales/backpressure/enabled 1
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$ bin/magento config:set sales/backpressure/enabled 1

Set the request limit per guest (IP address).

$ bin/magento config:set sales/backpressure/guest_limit 50
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$ bin/magento config:set sales/backpressure/guest_limit 50

Set the request limit for authenticated customers:

$ bin/magento config:set sales/backpressure/limit 10
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$ bin/magento config:set sales/backpressure/limit 10

Set the period of time (in seconds) for the request limit. Supported values 60, 3600, 86400 seconds. This time period is multiplied by three to calculate the timeout period:

$ bin/magento config:set sales/backpressure/period 60
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$ bin/magento config:set sales/backpressure/period 60

The following scenario describes how rate limiting can be configured.

Anonymous users are limited to 50 orders (sales/backpressure/guest_limit = 50) from a single IP address within one minute (sales/backpressure/period = 60). If they exceed the order limit, then they will have to wait three times the specified period of time (180 seconds) from their last request.
If an authorized customers attempts to place more than 10 orders (sales/backpressure/limit = 10) within the period of 60 seconds, then the user will not be able to place an order for a period of 180 seconds.

If you need to check a configuration, use the following CLI command:

Example:

$ bin/magento config:show | grep backpressure
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$ bin/magento config:show | grep backpressure

Response:

sales/backpressure/limit - 10
sales/backpressure/guest_limit - 50
sales/backpressure/period - 60
sales/backpressure/enabled - 1
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sales/backpressure/limit - 10
sales/backpressure/guest_limit - 50
sales/backpressure/period - 60
sales/backpressure/enabled - 1

Log contents

If rate limiting has been enabled for the payment information endpoint and the GraphQl mutation via the UI/CLI, but the Redis service connection for store log requests has not been configured in the app/etc/env.php file, then the rate-limiting will not apply. The behavior will be the same if this option is disabled, but the application logs (<magento-root>/var/log/system.log) will contain the following message:

...
[2022-11-11T15:46:32.716679+00:00] main.ERROR: Backpressure sliding window not applied. Invalid request logger type:  [] []
...
[2022-11-11T15:46:37.730863+00:00] main.ERROR: Backpressure sliding window not applied. Invalid request logger type:  [] []
...
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...
[2022-11-11T15:46:32.716679+00:00] main.ERROR: Backpressure sliding window not applied. Invalid request logger type:  [] []
...
[2022-11-11T15:46:37.730863+00:00] main.ERROR: Backpressure sliding window not applied. Invalid request logger type:  [] []
...

Example HTTP Responses

If rate limiting is applied to a REST request, then a response with HTTP status code 429 - Too Many Requests will be generated.

Example:

HTTP/1.1 429 Too Many Requests
...
Pragma: no-cache
Cache-Control: no-store
...
{"message":"Too Many Requests","trace":null}
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HTTP/1.1 429 Too Many Requests
...
Pragma: no-cache
Cache-Control: no-store
...
{"message":"Too Many Requests","trace":null}

If rate limiting is applied to a GraphQl request, then a response with HTTP status code 200 - Ok will be generated and all relevant information will be present in the response body.

Example:

HTTP/1.1 200 OK
...
Pragma: no-cache
Cache-Control: max-age=0, must-revalidate, no-cache, no-store
 ...
{
    "errors":[
        {
            "message":"Too Many Requests",
            "extensions":{"category":"graphql-too-many-requests"},
             "locations":[
                 {"line":2,"column":3}
             ],
             "path":["placeOrder"]
        }
    ],
    "data":{"placeOrder":null}
}
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HTTP/1.1 200 OK
...
Pragma: no-cache
Cache-Control: max-age=0, must-revalidate, no-cache, no-store
 ...
{
    "errors":[
        {
            "message":"Too Many Requests",
            "extensions":{"category":"graphql-too-many-requests"},
             "locations":[
                 {"line":2,"column":3}
             ],
             "path":["placeOrder"]
        }
    ],
    "data":{"placeOrder":null}
}