add jsonp

content/docs/client-side/jsonp.md

@@ -0,0 +1,37 @@
+---
+title: "JSONP"
+description: "Overview of JSONP."
+lead: "Overview of JSONP."
+date: 2020-10-06T08:49:31+00:00
+lastmod: 2020-10-06T08:49:31+00:00
+draft: false
+images: []
+menu:
+  docs:
+    parent: "client-side"
+weight: 630
+toc: true
+---
+
+## Definition
+
+JSONP (`JSON with padding`) is a technique used in web development to enable cross-origin data sharing between two domains. It exists primarily to bypass the same-origin policy imposed by web browsers, which restricts JavaScript from reading JSON cross-site.
+
+The same-origin policy is a security measure that prevents one website from interfering with another. However, sometimes it's necessary for a website to access data or resources from another domain, such as when using APIs provided by other services. JSONP provides a way to achieve this by exploiting the fact that `<script>` tags in HTML are not subject to the same-origin policy.
+
+Here's how JSONP works:
+
+1. Instead of making a regular AJAX request, the client includes a `<script>` tag in their HTML, pointing to the URL of the server providing the data.
+2. The server responds with a JavaScript file containing a JSON object wrapped in a function call. The name of the function is specified by the client as a query parameter in the URL.
+3. When the client receives the response, it executes the JavaScript code, which calls the specified function with the JSON data as an argument.
+4. The client can then process the JSON data as needed.
+
+JSONP exists because it provides a simple and effective way to bypass the same-origin policy and enable cross-origin data sharing between domains. Modern web development techniques such as CORS (`Cross-Origin Resource Sharing`) provide more secure and flexible ways to achieve cross-origin data sharing.
+
+## CSP Bypass
+
+JSONP can help an attacker to bypass `Content Security Policy`'s `script-src` directive if a domain with an exposed JSONP endpoint is included in the policy's value.
+
+## JSONP Endpoint List
+
+- [Github - zigoo0/JSONBee](https://github.com/zigoo0/JSONBee/blob/master/jsonp.txt)

content/docs/framework/express.md

@@ -51,6 +51,8 @@ toc: true
 - [vary](https://www.npmjs.com/package/vary):
 {{< /details >}}
 
+- [Express - Security updates](https://expressjs.com/en/advanced/security-updates.html)
+
 ## Query string parsing
 
 | URL                       | Content of request.query.foo in code                |