Tsup, a zero-config TypeScript bundler leveraging the speed of esbuild, saw a bump from version 3.3.0 to 3.4.0 on July 25th, 2020. While the core functionality remains consistent – simplifying the bundling process for TypeScript libraries for developers – a closer look reveals underlying improvements. Both versions share identical core dependencies, including cac for command-line argument parsing, chalk for terminal styling, joycon for configuration file management, rollup and rollup-plugin-dts for bundling and declaration file generation, esbuild for lightning-fast builds, and sucrase for faster development builds and chokidar for file watching. Similarly, the development dependencies remained unchanged between the two releases, including those used for testing, formatting, and type checking.
The key difference lies primarily in the distributed package data. Version 3.4.0 saw an increase in unpacked size to 684924 bytes, compared to 3.3.0's 574651 bytes, indicating that some code changes were integrated, be it performance improvements, bug fixes or some additional features. Both versions keep the file count at 11. The release also came within a day of the previous version. For developers, this suggests a focus on either rapidly addressing identified issues from the previous version or incremental enhancement rather than a major overhaul and ensures a more robust and refined bundling experience without introducing breaking changes. Always prefer the latest stable version as that contains improvements and bug fixes.
All the vulnerabilities related to the version 3.4.0 of the package
tsup DOM Clobbering vulnerability
A DOM Clobbering vulnerability in tsup v8.3.4 allows attackers to execute arbitrary code via a crafted script in the import.meta.url to document.currentScript in cjs_shims.js components
esbuild enables any website to send any requests to the development server and read the response
esbuild allows any websites to send any request to the development server and read the response due to default CORS settings.
esbuild sets Access-Control-Allow-Origin: * header to all requests, including the SSE connection, which allows any websites to send any request to the development server and read the response.
https://github.com/evanw/esbuild/blob/df815ac27b84f8b34374c9182a93c94718f8a630/pkg/api/serve_other.go#L121 https://github.com/evanw/esbuild/blob/df815ac27b84f8b34374c9182a93c94718f8a630/pkg/api/serve_other.go#L363
Attack scenario:
http://malicious.example.com).fetch('http://127.0.0.1:8000/main.js') request by JS in that malicious web page. This request is normally blocked by same-origin policy, but that's not the case for the reasons above.http://127.0.0.1:8000/main.js.In this scenario, I assumed that the attacker knows the URL of the bundle output file name. But the attacker can also get that information by
/index.html: normally you have a script tag here/assets: it's common to have a assets directory when you have JS files and CSS files in a different directory and the directory listing feature tells the attacker the list of files/esbuild SSE endpoint: the SSE endpoint sends the URL path of the changed files when the file is changed (new EventSource('/esbuild').addEventListener('change', e => console.log(e.type, e.data)))The scenario above fetches the compiled content, but if the victim has the source map option enabled, the attacker can also get the non-compiled content by fetching the source map file.
npm inpm run watchfetch('http://127.0.0.1:8000/app.js').then(r => r.text()).then(content => console.log(content)) in a different website's dev tools.Users using the serve feature may get the source code stolen by malicious websites.