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How to identify suspicious API traffic

Image: Adobe Stock / Kitreel

Harold Bell, Director of Content Marketing, Noname Security, gives his top five tips for identifying and deterring suspicious API traffic.

With the increasing reliance on APIs, detecting suspicious API traffic has become crucial to ensure the security and integrity of these interactions. Suspicious API traffic poses a huge threat to the overall system and its data; the traffic can indicate malicious intent such as unauthorised access attempts, data breaches, or even potential attacks targeting vulnerabilities in the API infrastructure.

API traffic refers to the data and requests that are transmitted between different applications or systems using APIs. This allows software programs to communicate and exchange information, enabling seamless integration and interaction between various platforms. API traffic also involves the transfer of data, such as requests for data retrieval or updates, between the client application and the server hosting the API.

APIs generate more traffic and individual calls than traditional web applications serving HTML and JavaScript. The automated nature of APIs generates a multitude of calls in order to render a page that would require a single HTML request. 

Malicious or malformed requests are therefore diluted in a larger volume of calls generated by well-behaving automated systems, making it difficult to detect by traditional inline solutions using static security rules.

Common sources of suspicious API traffic

Unusual patterns of request frequency – if an API receives an unusually high number of requests within a short period of time, it could be an attempt to overwhelm the API server
Unusual usage patterns – this includes calling API endpoints in an unexpected way, or skipping over standard steps, which could be a sign of malicious intent
Unauthenticated or unauthorised access attempts – requests that do not include proper authentication credentials or attempt to access restricted resources
Malicious payloads or injection attempts – API traffic containing malicious payloads, such as SQL injection attempts or cross-site scripting (XSS) attacks
Unusual data patterns or content – API traffic that includes suspicious or unexpected patterns of data, such as large amounts of sensitive information or abnormal data formats
High error rates or unusual response codes – a sudden increase in error rates or the presence of uncommon response codes in API traffic can suggest suspicious activity.

Below, I have outlined the top five proactive measures for defending against suspicious API traffic activity, enabling organisations to identify and respond in a timely manner.

  1. Implement secure authentication mechanisms

Implementing secure authentication and authorisation mechanisms is crucial for protecting sensitive information and ensuring the integrity of user accounts. By employing robust security measures, organisations can mitigate the risk of unauthorised access and data breaches.

One effective method of authentication is the use of strong and complex passwords to enhance security. Additionally, implementing a multi-factor authentication (MFA) system to add an extra layer of protection, ensuring users to provide additional verification, such as a one-time password sent to their mobile device. Lastly, API Token scopes would also be beneficial. 

Implementing secure authentication and authorisation mechanisms should also include measures such as encryption of sensitive data, secure session management, and regular security audits 

In terms of authorisation, role-based access control (RBAC) is a widely adopted approach. RBAC grants access privileges based on assigned roles. This ensures that users only have access to the resources and functionalities that are necessary for their job responsibilities.

  1. Prioritise machine learning-based log analysis and anomaly detection

Analysing system logs and detecting anomalies are crucial for effective cybersecurity. Advanced algorithms and machine learning technologies can be used to identify abnormal patterns or behaviours that may indicate a security breach or unauthorised access.

Log analysis is the process of gathering and examining log data from various sources, such as servers, firewalls, and network devices. This data can offer insights into user activities, system performance, and potential security risks. Through log analysis, organisations can track and monitor network activity and proactively respond to security incidents.

Anomaly detection techniques play a crucial role in identifying suspicious activities across various data points that deviate from normal patterns. These anomalies can include unusual login attempts, request patterns, unauthorised access attempts, or abnormal data transfers. By leveraging machine learning algorithms, organisations can establish baseline behaviour and detect anomalies with a higher degree of accuracy.

  1. Implement rate limiting and access controls

Implementing rate limiting and access controls helps to ensure the stability and security of your system. By limiting the number of requests that can be made within a certain time, you can prevent abuse and protect your resources. 

Additionally, implementing access controls allows you to restrict access to specific endpoints or features based on user roles or permissions. Together, rate limiting, and access controls are essential components of a robust security strategy.

  1. Regularly update and patch API endpoints

Regularly updating and patching API endpoints is crucial for maintaining the security and functionality of your application. By staying proactive and implementing regular updates and patches, API endpoints are protected against potential vulnerabilities such as bugs and security threats. 

It’s important to establish a systematic process for updating and patching API endpoints to guarantee that your application remains secure and reliable.

  1. Perform security audits and penetration testing

Performing security audits and penetration testing is crucial for the overall security of a system or network. Conducting audits ensures potential vulnerabilities can be identified and addressed proactively. Penetration testing, on the other hand, involves simulating real-world attacks to test the effectiveness of existing security measures.

During a security audit, various aspects of the system or network are examined, including hardware, software, processes, and configurations. This identifies misconfigurations, outdated software versions, or inadequate security controls – which are exploited by malicious actors. Penetration testing attempts to exploit vulnerabilities and gain unauthorised access to the system or network. 

This testing is usually performed by ethical hackers who use a combination of automated tools and manual techniques to simulate real-world attack scenarios to address vulnerabilities before they are exploited further.

A proactive approach is key

To effectively detect suspicious API traffic, organisations need to implement robust monitoring systems and employ advanced analytics and machine learning algorithms. This is only the first step; organisations can then implement subsequent countermeasures to prevent further damage. 

The most effective way of achieving this is partnering with a dedicated API security provider, one that is viewed as more than simply a vendor. This will help to ensure that API security policies and tools stay ahead of the evolving cybersecurity landscape, enabling organisations to proactively identify and respond to security threats, minimising the risk of data breaches, financial losses, and reputational damage. At the same time, businesses can focus on what matters to them – improving the speed at which they can grow and scale. 

Harold Bell
Harold Bell
Director of Content Marketing, Noname Security

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