API Security

Application programming interfaces (APIs) importance increases with the enlarging significance of integration and interconnectivity in the sphere of communications. APIs widely support the delivery of new products and services by integrating functionality from external services.

API integrations bring forward the authentication and authorization difficulties. For organizations implementing API management to respond to rapid changes in customer demands ensuring the APIs appropriate levels of security is a vital necessity.

The primary purpose of API Security is to comprehend and alleviate the vulnerabilities peculiar to API and its security risks by focusing on strategies and solutions that allow application software and services to integrate and products and services to communicate.

API vulnerabilities

Broken object-level authorization

Access to a data source using input from the user may have a Level Access Control issue if API does not check permissions and let API endpoints vulnerable to the so-called broken object-level authorization. Attackers can get through exploiting the ID of an object sent within the request.

Broken User Authentication

Authentication mechanisms flaws may endanger API security if attackers compromise authentication tokens or identification systems by exploiting implementation drawbacks.

Excessive Data Exposure

Data objects fully exposed to the client application filters may become sensitive to the attackers if they go straight to the API.

Lack of Resources & Rate Limiting

An excessive amount of API calls or payload sizes can impact the API server performance and lead to Denial of Service (DoS) and brute force attacks.

Broken Function Level Authorization

Indistinctly divided administrative and regular functions alongside with various hierarchies and roles may lead to authorization flaws and expose the API endpoints to anonymous or non-privileged users.

Mass Assignment

Mass assignment usually occurs as a result of binding the client data to the data model with no proper filtering and transforming the payload into an object and storing it. Attackers can use the GET request data and change object properties.

Security Misconfiguration

API servers configuration issues, such as unpatched systems, open cloud storage, unprotected files, and directories, missing, outdated, or misconfigured TLS, deficient CORS policy or security headers, verbose error messages with sensitive information, open storage or server management panels, and unnecessary HTTP methods or other features.


Attackers send malicious data to the interpreter as a part of a request by developing API calls that include commands such as SQL, NoSQL, OS, or others for the API or the backend to execute.

Improper Assets Management

Staging, testing, beta, or other non-production versions of the API with the endpoints that have access to production data but lack proper protection can become a target for attackers.

Insufficient Logging & Monitoring

With the logs not protected for integrity, and not integrated into Security Information and Event Management (SIEM) systems, and poorly designed, the system becomes vulnerable to tampering with, extracting, or destroying data. In such cases, breaches are more likely to be detected by external parties in months.

API Security approach

APIs with vulnerabilities can expose sensitive data. APIs Security approaches must be developed depending on the kind of data businesses transfer and based on a need for a trusted environment with proper authentication and authorization policies.

Security mechanisms differ from simple protection with an API key to OAuth (Open Authorization) for critical external APIs.

API keys are typically not considered secure; if one steals the key, they can use it for an unspecified time unless it is revoked or regenerated. An API key is usually accessible to the client, and the only secure way of using it is together with HTTPS/SSL.

OAuth is a delegated access framework for REST APIs. It enables obtaining limited access without sharing passwords and separates authentication from authorization. OAuth supports use scenarios for various device capabilities.

The most common authentication and authorization methods include:

  • Static strings embedded by the API caller or client as a token in the request and used are like passwords.
  • The dynamic token is a nonce inserted into the token that has a time to live (TTL) and is otherwise called a time-based token. After the expiration of the time, the request is forbidden. An example of such a token is a JSON Web Token.
  • User-delegated tokens are granted based on user authentication and used in trivet systems to provide access to an API on behalf of a user. These tokens are such as OAuth.

Ways to provide security can be as following:

  • Identifying the vulnerabilities of the operating system, network, drivers, and API components; detecting security issues and tracking data leaks by using sniffers;
  • Placing quotas on API calls and tracking its use to indicate possible abuse or a programming error such as calling the API in an overlong loop; making protection rules against spikes and Denial-of-Service attacks;
  • Using the encryption with a method like TLS and signatures to ensure proper data access. Encrypt all exchanges with TLS, the one-way, or mutual encryption;
  • Authentication through an API key or basic access authentication, to prevent an easy hack on the system;
  • Delegating authorization and authentication of your APIs with OAuth and OpenID Connect that adds an identity layer to extend an OAuth with ID tokens;
  • Using experienced Antivirus systems or ICAP Internet Content Adaptation Protocol (ICAP) servers to enhance security options;
  • Auditing and logging relevant information on the server to be able to turn logs into resources for debugging if necessary, and monitoring dashboards to track the API consumption;
  • Adding the version on all APIs to be able to handle different versions;
  • Using IP White and Blacklists for access restriction purposes, limiting the number of administrators, and hiding sensitive information in all interfaces;
  • Using JSON or XML validation to check the data the server accepts, the content that consumers are sending, and parameters (string, integer…) to prevent any SQL injection or XML assault;
  • Securing all the API vulnerabilities;
  • Firewalling an API by executing basic security mechanisms like controlling the message size and SQL injections on the MDZ layer, and then forward to the LAN layer with advanced security mechanisms;
  • Using an API gateway to authenticate traffic, analyze and control APIs usage ways.
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