When it comes to the adoption of Application Programming Interfaces, or APIs, the technology is growing rapidly and has been for quite some time. More businesses are turning to APIs for their internal and external operations, truly making them a core component of day-to-day business. It's encouraging to see the rise in API adoption, but it's also crucial to understand the security implications of that growth and how you can mitigate them. Along with adoption, API security vulnerabilities will continue to rise, and organizations must be prepared.
This post will examine serious API security vulnerabilities and how to protect yourself.
What Is an API Vulnerability?
An API vulnerability is a type of security flaw that allows attackers to access sensitive data or execute other malicious actions. API vulnerabilities can occur when an API is poorly designed or implemented or inadequately secured.
Hackers can exploit these API vulnerabilities to launch different attacks, such as denial-of-service attacks, or to gain access to confidential information. Overall, a vulnerability is an opening for someone to take advantage of with malicious intent, and each can compromise API security in various ways.
Why Is API Security Important?
API security is essential because it helps to protect data and prevent unauthorized access to resources. Organizations can achieve API security through various means, such as authentication, authorization, and encryption. By implementing API security measures, companies can ensure that only authorized users can access their data and resources.
Additionally, API security can help to protect data from being intercepted or modified by unauthorized users. The most comprehensive list of potential API security issues is the OWASP API Security Top 10, a derivative of the OWASP Top 10 Vulnerabilities many are likely familiar with.
OWASP API Security Top 10
The OWASP API Security Top 10 is a comprehensive list of the most critical API security risks compiled by security experts worldwide. This list serves as a standard guideline for businesses and developers to understand and mitigate the risks associated with API security. The OWASP API Security Top 10, updated in 2023, includes:
Broken Object Level Authorization (BOLA): This occurs when an API does not properly enforce access controls, allowing attackers to manipulate object IDs to gain unauthorized access to sensitive data.
Broken User Authentication: Weak authentication mechanisms can allow attackers to compromise user accounts and gain unauthorized access.
Broken Object Property Level Authorization (BOPLA): This vulnerability arises when APIs fail to enforce proper authorization checks on object properties, leading to unauthorized access or modification.
Unrestricted Resource Consumption: APIs that do not limit resource usage can be exploited to consume excessive resources, leading to denial-of-service (DoS) attacks.
Broken Function Level Authorization (BFLA): This occurs when APIs do not properly enforce authorization checks at the function level, allowing attackers to execute unauthorized functions.
Unrestricted Access to Sensitive Business Flows: APIs that expose sensitive business processes without proper access controls can be exploited to gain unauthorized access to critical operations.
Server Side Request Forgery (SSRF): This vulnerability allows attackers to manipulate server-side requests, potentially accessing internal systems and sensitive data.
Security Misconfiguration: Inadequate security configurations can leave APIs vulnerable to various attacks, including data breaches and unauthorized access.
Improper Inventory Management: Failing to manage and secure all deployed API versions can lead to the exploitation of deprecated or insecure APIs.
Unsafe Composition of APIs: Combining multiple APIs without proper security measures can introduce vulnerabilities and increase the attack surface.
Understanding these top 10 API security risks is essential for protecting sensitive data and preventing unauthorized access to your API. Based on this info, how would we mitigate some of these vulnerabilities? Let's take a look at this next.
Mitigating API Security Vulnerabilities
Mitigating API security vulnerabilities requires a combination of awareness, education, and the implementation of robust security protocols. Here are some strategies to help mitigate API security vulnerabilities:
Implement Strong Authentication and Authorization Mechanisms: Ensure that only authorized users can access your API using strong authentication methods, such as multi-factor authentication and comprehensive authorization checks.
Use an API Gateway: An API gateway can manage and monitor API traffic, enforce security policies, and provide a centralized point for implementing security measures.
Implement Rate Limiting and Throttling: Prevent denial-of-service (DoS) attacks and brute force attacks by limiting the number of API requests that can be made per unit of time.
Use Encryption: Protect sensitive data in transit and at rest by using encryption protocols such as HTTPS and TLS.
Regularly Test and Scan for API Vulnerabilities: Conduct regular security testing and scanning to identify and fix potential security flaws in your APIs. This includes using tools like SAST and DAST platforms.
Implement Object-Level Authorization Checks: Ensure that proper authorization checks are in place to prevent unauthorized access to sensitive data at the object level.
Use Secure Protocols for Communication: Always use secure communication protocols, such as HTTPS and TLS, to protect data from being intercepted or tampered with.
Monitor API Traffic and Logs: Continuously monitor API traffic and logs to detect and promptly respond to security incidents.
By implementing these strategies, you can significantly reduce the risk of API security vulnerabilities and protect your sensitive data.
How Can an API Be Insecure?
As alluded to in our OWASP API Top 10 coverage above, An API can be insecure in several ways. Let's discuss some of the most common ways in detail, including the particulars on how to protect against these common API vulnerabilities.
1. Broken Access Control
Access control in APIs is a critical security measure that controls who can access data and functionality within an API. However, if access control is not implemented correctly, it can leave APIs vulnerable to attack.
One type of attack that can exploit poor access control is known as a broken access control attack. This type of attack occurs when a hacker/attacker can bypass the security measures in place and gain unauthorized access to data or functionality.
To protect against broken access control attacks, it's essential to implement proper access control measures in your API. This includes appropriately implementing authentication and authorization checks. It's also essential to keep your access control measures up to date as new vulnerabilities are discovered.
To protect against broken access control attacks, it's essential to implement proper access control measures in your API.
2. Broken Authentication Issues
Since APIs rely on authentication to grant access to data and resources, any authentication process flaw can jeopardize the API’s security. Broken authentication is a significant security issue in APIs, as it can allow attackers to access data and resources they should not have access to.
Compromised authentication tokens can allow attackers to impersonate legitimate users, leading to potential data breaches and unauthorized access.
There are many ways in which authentication can be broken, such as using weak or easily guessed passwords, failing to validate user cookies, or lacking JWT expiration properly.
There are a few things that you can do to prevent broken authentication issues in your APIs:
Implement proper authentication and session management controls—this includes using strong passwords, encrypting sensitive data, and using session timeouts.
Restrict access to your API to only those who need it—this can be done using an access control list or an API key.
Monitor access to your API and look for suspicious activity—this can help you to detect and stop attacks before they happen.
3. Injection Attacks
Injection attacks are a type of attack where code (malicious) is injected into a system. This can be done through a variety of means but is often done through APIs. Injection attacks can gain access to sensitive data, execute unwanted actions, or cause a denial-of-service condition.
In injection attacks, the attacker takes advantage of the fact that the API accepts input from untrusted sources. By injecting malicious code into the API through user input, the attacker can cause the API to execute unwanted actions or return sensitive data that the attacker can then use to gain access to the system.
To protect against injection attacks, validating all input received through an API is essential. This includes ensuring that the input is of the expected type, size, and format. Additionally, it’s essential to escape any special characters used in injection attacks. By taking these precautions, it’s possible to reduce the risk of injection attacks significantly.
4. Excessive Data Exposure
The proliferation of APIs has increased data exposure risks as more sensitive data is being shared via these interfaces. In many cases, API developers do not adequately secure their APIs, leading to data leaks and other security issues.
This type of data leak can have severe consequences for the individuals whose data has been exposed and the organization responsible for the API.
To avoid these risks, organizations should carefully control access to their APIs, ensure that only authorized parties can access the data, and protect sensitive files and directories.
5. Lack of Rate Limiting
Rate limiting is a way to control the rate at which an API processes requests.
Lack of rate limiting in APIs can lead to excessive requests that can overload the system and cause it to fail. This can result in a loss of data and service outages. Rate limiting is critical to API design and should be implemented to ensure the system's stability.
By limiting the number of incoming requests that can be made per unit of time, rate limiting can help prevent resource overuse, improve performance, and reduce the risk of denial-of-service attacks.
Rate limiting is a way to control the rate at which an API processes requests.
6. Insecure Direct Object Reference
Insecure direct object reference (IDOR) is a type of security vulnerability that occurs when an application references an object using a direct reference. A hacker/attacker can exploit this to gain access to sensitive data or perform unauthorized actions.
For example, a GET request is used to fetch user details such as name, card details, family member details, etc., and the API relies on the user ID, which the client sends as a parameter. If the user ID is guessable or can be brute forced, an attacker can change the user ID in the URL and fetch the sensitive details of other users.
To prevent this attack, it's essential to never reference an object using a direct reference. Instead, applications should use indirect references that are not guessable or predictable. For example, an application might use a UUID to reference an object.
How Do I Check API Vulnerabilities?
API vulnerabilities can be difficult to track down and fix. However, there are a few ways you can check for them.
One way is to use a web application security scanner such as the StackHawk DAST scanner. These tools can help you identify common vulnerabilities, such as SQL injection.
Another way to check for API vulnerabilities is to review your code. This can be done manually or with a static code analysis tool. Reviewing your code can help you find potential security flaws, such as incorrect input validation or the insecure storage of sensitive data.
Maintaining an accurate inventory of API versions is crucial to prevent security issues, particularly managing deprecated API versions. This is made even easier when using StackHawk's API Discovery feature to find and catalog all existing versions of your APIs.
Finally, you can also monitor your API for unusual activity. This can help you detect potential attacks, such as denial-of-service attacks. Monitoring your API can also help you identify unauthorized access to sensitive data.
Conclusion
An API is a gateway to access information and data. A vulnerable API can lead to a breach of data and unauthorized access. An API can be susceptible for several reasons—design, coding, configuration, etc.
This post focused on API security vulnerabilities and the steps you can take to prevent them. We hope you enjoyed it and found it helpful. For more information on how StackHawk can help you find and fix the most common API vulnerabilities, sign up for a free trial to get started on your own, or contact our team of API security experts for more info.
