Overview of AsyncOS API for Cisco Secure Email Gateway

The AsyncOS API for Cisco Secure Email Gateway (or AsyncOS API) is a representational state transfer (REST) based set of operations that provide secure and authenticated access to the email gateway reports, report counters, and tracking. You can retrieve the email gateway reporting and tracking data using the API. In this release you can query for configuration information. Posting configuration changes is not supported in this release.

For more information, refer to the Swagger API help. To view the API help, access the new web interface of the email gateway, click the help icon on the top right corner of the page and select API Help: Swagger.

This chapter contains the following sections:

Prerequisites for Using AsyncOS API

To use AsyncOS API, you need the knowledge of:

    • HTTP, which is the protocol used for API transactions. Secure communication over TLS.

    • JavaScript Object Notation (JSON), which the API uses to construct resource representations.

    • JSON Web Token (JWT)

  • A client or programming library that initiates requests and receives responses from the AsyncOS API using HTTP or HTTPS, for example, cURL. The client or programming library must support JSON to interpret the response from the API.

  • Authorization to access the AsyncOS API. See Authorization.

  • AsyncOS API enabled using web interface or CLI. See Enabling AsyncOS API.


Note

Version 1.0 APIs are not supported from Cisco Email Security 13.0 release and later. Instead version 2.0 APIs are used.

Enabling AsyncOS API

Before You Begin

Make sure that you are authorized to access the IP Interfaces page on the web interface or the interfaceconfig command on CLI. Only administrators, email administrators, cloud administrators, and operators are authorized.

You can also enable the AsyncOS API using the interfaceconfig command in CLI.

Procedure

Step 1

Log in to the web interface.

Step 2

Choose Network > IP Interfaces.

Step 3

Edit the Management interface.

Note

 

  • You can enable AsyncOS API on any IP interface. However, Cisco recommends that you enable AsyncOS API on the Management interface.

  • You must not enable APIs on multiple management interface.

Step 4

Under the AsyncOS API (Monitoring) section, depending on your requirements, select HTTP, HTTPS, or both and the ports to use.

Note

 
AsyncOS API communicates using HTTP / 1.1.

If you have selected HTTPS and you want to use your own certificate for secure communication, see Securely Communicating with AsyncOS API.

Note

 
Cisco recommends that you always use HTTPS in the production environment. Use HTTP only for troubleshooting and testing the API.

Step 5

Submit and commit your changes.

Securely Communicating with AsyncOS API

You can communicate with AsyncOS API over secure HTTP using your own certificate.


Note
Do not perform this procedure if you are already running the web interface over HTTPS and using your own certificate for secure communication. AsyncOS API uses the same certificate as web interface, for communicating over HTTPS.

Procedure

Step 1

Set up a certificate using the certconfig command in the CLI. For instructions, refer the User Guide or Online Help.

Step 2

Change the HTTPS certificate used by the IP interface to your certificate using the interfaceconfig command in CLI. For instructions, refer the User Guide or Online Help.

Step 3

Submit and commit your changes.

AsyncOS API Authentication and Authorization

This section explains about the authentication methods, the user roles which can access APIs, and how to query for APIs accessible to a user.

Authentication

Submit the email gateway's username and password with all the requests to the API, in the Base64-encoded format or with a JSON Web Token. The user inactivity timeout settings in the email gateway apply to the validity of a JWT. If a request does not include valid credentials in the Authorization header, the API sends a 401 error message. You can use any base64 library to convert your credentials into base64-encoded format.


Note
The email gateway allows you to invoke AsyncOS APIs by including access tokens that are retrieved from Identity Providers (IDPs) that support OpenID Connect 1.0. For more details on how to use AsyncOS APIs with external IDPs, see the "System Administration" chapter of the User Guide for AsyncOS 14.0 for Cisco Secure Email Gateway.

Authenticating API Queries with JSON Web Token

You can generate a JSON Web Token (JWT) and use it with your API queries.


Note

The user inactivity timeout settings in the email gateway applies to the validity of a JWT. The email gateway checks every API query with a JWT, for its time validity. If a JWT is found to be within 5 minutes of time validity, after which it will time out, a new refresh JWT is sent with the response header. You must use this new refresh JWT with API queries, or generate a new one.

Synopsis 

POST /esa/api/v2.0/login

Use the syntax below for two factor authentications:

POST /esa/api/v2.0/login/two_factor

Body Parameters

Use Base64 encoded credentials.

{
    "data": 
    {
        "userName":"YWRtaW4=",
        "passphrase":"aXJvbnBvcnQ="
    }
}

Request Headers

Host, Accept, Authorization

Response Headers

Content-Type, Content-Length, Connection

This example shows a query to log in with Base64 encoded credentials, and generate a JWT.

Sample Request

POST /esa/api/v2.0/login
HTTP/1.1
Content-Type: application/json
cache-control: no-cache
User-Agent: curl/7.54.0
Accept: */*
Host: esa.cisco.com:6080
accept-encoding: gzip, deflate
content-length: 95
Connection: keep-alive
{
    "data": 
    {
        "userName":"YWRtaW4=",
        "passphrase":"aXJvbnBvcnQ="
    }
}

Sample Response

HTTP/1.1 200 OK
Server: API/2.0
Date: Mon, 26 Nov 2018 07:22:47 GMT
Content-type: application/json
Content-Length: 618
Connection: close
Access-Control-Allow-Origin: *
Access-Control-Allow-Headers: content-type, jwttoken, mid, h, email
Access-Control-Allow-Credentials: true
Access-Control-Allow-Methods: GET, POST, DELETE, OPTIONS
Access-Control-Expose-Headers: Content-Disposition, jwtToken

{
    "data": {
        "userName": "admin",
        "is2FactorRedirectRequired": "false",
        "role": "Administrator",
        "email": [],
        "jwtToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyTmFtZSI6ImFkbWluIiwiaXM
         yRmFjdG9yQ2hlY2tSZXF1aXJlZCI6ZmFsc2UsImNvb2tpZSI6IlRucEZOVTFFWTNwTlZFMDlDanRMYVR
         oeENqdFpiV1J6VFVSQk5VMURNWGRpTWxGMVdUSnNlbGt5T0hWWk1qbDBUMnBaZDA5RVFUMEtcbk8xVkh
         PWHBrUnpGb1lteEtNV0p1VW5CaVYxVjJUbmswTUV4cVFUMEtPMVJVUlhkTlJsazNUVlJKZFUxRE5IZE1
         WRWw1VFdwek1FMXFcblNUVlNhazVDVDBWRk1rOUVaM2xTUlVreVRYcGtSazFwTVVSTlZFMHpUbFZXUjA1
    }
}

Authorization

The AsyncOS API is a role based system, the scope of API queries is defined by the role of the user. The email gateway users with the following roles can access the AsyncOS API:

  • Administrator

  • Operator

  • Technician

  • Read-Only Operator

  • Guest

  • URL Filtering Administrator

  • Email Administrator

  • Help Desk User


Note

  • Externally authenticated users can access the API.

  • Custom roles, delegated by the administrator can also access the APIs.

AsyncOS API Requests and Responses

AsyncOS API Requests

Requests made to the API have the following characteristics:

  • Requests are sent over HTTP or HTTPS

  • Each request must contain a valid URI in the following format:

    http://{appliance}:{port}/esa/api/v2.0/{resource}/{resource_attributes}
    https://{appliance}:{port}/esa/api/v2.0/{resource}/{resource_attributes}

    where:

    • {appliance}:{port}
      is the FQDN or the IP address of the email gateway and the TCP port number on which the email gateway is listening. 
    • {resource}
      is the resource you are attempting to access, for example, reports, tracking, quarantine, configuration, or other counters. 
    • {resource_attributes}
      are the supported attributes for a resource, for example, duration, and so on.
  • Each request must contain user credentials, or a valid authorization header.
  • Each request must be set to accept: 
    application/json
  • Requests sent over HTTPS (using your own certificate) must contain your CA certificate. For example, in case of cURL, you can specify the CA certificate in the API request as follows: 
    curl --cacert <ca_cert.crt> -u"username:password"
    https://<fqdn>:<port>/esa/api/v2.0/{resource}/{resource_attributes}

Note
API requests are case sensitive and should be entered as shown in this guide.

AsyncOS API Responses

This section explains the key components of the responses, and various HTTP error codes.

Key Components of Responses

Components

Values

Description

Status Code and Reason

See HTTP Response Codes.

HTTP response code and the reason.

Message Header

Content-Type 

application/json

Indicates the format of the message body.

Content-Length

n/a

The length of the response body in octets.

Connection 

close

Options that are desired for the connection.

Message Body

n/a

The message body is in the format defined by the Content-Type header. The following are the components of the message body:

  1. URI. The URI you specified in the request to the API.

    Example

    "esa/api/v2.0/config/"

  2. Counter group and/or counter name

    Example

    reporting/mail_security_summary

  3. Query parameters

    Example

    startDate=2017-01-30T00:00:00.000Z&endDate=2018-01-
30T14:00:00.000Z

  4. Error (Only for Error Events). This component includes three subcomponents—message, code, and explanation.

    Example 

    "error": {"message": "Unexpected attribute 
- starts_with.","code": "404", "explanation":
"404 = Nothing matches the given URI."}

    If the message body contains empty braces ({}), it means that the API could not find any records matching the query.

HTTP Response Codes

The following is a list of HTTP response codes returned by AsyncOS API:

  • 200

  • 202

  • 300

  • 301

  • 307

  • 400
  • 401

  • 403

  • 404
  • 406
  • 413
  • 414
  • 500
  • 501
  • 503
  • 505 

For descriptions of these HTTP response codes, refer the following RFCs:

  • RFC1945
  • RFC7231

AsyncOS APIs - Rate Limits

The maximum number of concurrent API requests allowed is 45. However, the effective number of requests that can be processed simultaneously (perceived limit) varies depending on the memory consumed by the API requests being processed and the API response time.

For example, if you initiate 45 API requests concurrently and assume that after 20 seconds, 11 of those requests have been successfully processed and completed. Since 11 requests are complete, you can initiate 11 more requests.

If you exceed this limit, you will receive the 502: Bad Gateway error response code if the Trailblazer port is used. In case the request is sent directly to the API server port, then the connection is rejected without any response code.


Note

The 502: Bad Gateway error response code will be modified in the upcoming releases.