How to Prevent Cross-Origin Resource Sharing (CORS) Attacks
Cross-origin resource sharing (CORS) is a mechanism that allows restricted resources on a web page to be requested from another domain outside the domain from which the resource originated. CORS is a security measure that helps to prevent malicious attacks on web applications. In this tutorial, we will discuss how to prevent CORS attacks.
Use a Content Security Policy (CSP)
A content security policy (CSP) is a security measure that helps to prevent malicious attacks on web applications. It is a set of rules that define which resources can be loaded on a web page. CSPs can be used to restrict the types of resources that can be loaded on a web page, such as scripts, images, and stylesheets. This helps to prevent malicious code from being injected into a web page.To implement a CSP, you need to add a
Content-Security-Policy header to your web page. This header contains a set of rules that define which resources can be loaded on the page. For example, the following CSP header will only allow scripts from the same origin to be loaded on the page:
Content-Security-Policy: script-src 'self'Use HTTP Strict Transport Security (HSTS)
HTTP Strict Transport Security (HSTS) is a security measure that helps to prevent malicious attacks on web applications. It is a policy that tells browsers to only access a website over a secure connection (HTTPS). This helps to prevent attackers from intercepting requests and injecting malicious code into the website.To implement HSTS, you need to add a
Strict-Transport-Security header to your web page. This header contains a set of rules that define which resources can be loaded over a secure connection. For example, the following HSTS header will only allow scripts from the same origin to be loaded over a secure connection:
Strict-Transport-Security: script-src 'self'Use Subresource Integrity (SRI)
Subresource Integrity (SRI) is a security measure that helps to prevent malicious attacks on web applications. It is a policy that tells browsers to only load resources from trusted sources. This helps to prevent attackers from injecting malicious code into a web page.To implement SRI, you need to add a
Subresource-Integrity header to your web page. This header contains a set of rules that define which resources can be loaded on the page. For example, the following SRI header will only allow scripts from the same origin to be loaded on the page:
Subresource-Integrity: script-src 'self'Use Access-Control-Allow-Origin (ACAO)
Access-Control-Allow-Origin (ACAO) is a security measure that helps to prevent malicious attacks on web applications. It is a policy that tells browsers to only allow requests from trusted origins. This helps to prevent attackers from accessing resources from other domains.To implement ACAO, you need to add an
Access-Control-Allow-Origin header to your web page. This header contains a set of rules that define which origins can access the page. For example, the following ACAO header will only allow requests from the same origin to access the page:
Access-Control-Allow-Origin: 'self'Use Access-Control-Allow-Credentials (ACAC)
Access-Control-Allow-Credentials (ACAC) is a security measure that helps to prevent malicious attacks on web applications. It is a policy that tells browsers to only allow requests with credentials from trusted origins. This helps to prevent attackers from accessing resources from other domains.To implement ACAC, you need to add an
Access-Control-Allow-Credentials header to your web page. This header contains a set of rules that define which origins can access the page with credentials. For example, the following ACAC header will only allow requests with credentials from the same origin to access the page:
Access-Control-Allow-Credentials: 'self'Conclusion
In this tutorial, we discussed how to prevent cross-origin resource sharing (CORS) attacks. We discussed how to use a content security policy (CSP), HTTP strict transport security (HSTS), subresource integrity (SRI), access-control-allow-origin (ACAO), and access-control-allow-credentials (ACAC) to help prevent malicious attacks on web applications.
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