Webpack-dev-middleware version 1.10.2 is a minor update to version 1.10.1, providing a development middleware solution for Webpack that serves live bundles directly from memory to a directory, improving development workflows. The core functionality remains consistent, offering features like on-the-fly code recompilation and hot module replacement, significantly speeding up the development cycle by eliminating the need for manual builds and server restarts.
Examining the provided data reveals minimal changes between the two versions, with identical dependencies, devDependencies, peerDependencies, license, repository information, and author. Crucially, developers can expect dependency management and webpack compatibility to remain consistent between versions. The primary difference lies in the release date. Version 1.10.2 was released on April 22, 2017, while version 1.10.1 was released on February 18, 2017. This suggests that version 1.10.2 likely contains bug fixes or minor performance improvements implemented during the intervening period.
For developers already using webpack-dev-middleware, upgrading to 1.10.2 should be straightforward, requiring only a simple version update in their package.json file. It is recommended to consult the changelog (available on the project's GitHub repository) for a detailed account of the changes, including bug fixes and performance enhancements. Because these versions don't have major differences, migrating between them should be easy and safe. This middleware is essential for Webpack-based projects aiming for faster development.
All the vulnerabilities related to the version 1.10.2 of the package
Path traversal in webpack-dev-middleware
The webpack-dev-middleware middleware does not validate the supplied URL address sufficiently before returning the local file. It is possible to access any file on the developer's machine.
The middleware can either work with the physical filesystem when reading the files or it can use a virtualized in-memory memfs filesystem. If writeToDisk configuration option is set to true, the physical filesystem is used: https://github.com/webpack/webpack-dev-middleware/blob/7ed24e0b9f53ad1562343f9f517f0f0ad2a70377/src/utils/setupOutputFileSystem.js#L21
The getFilenameFromUrl method is used to parse URL and build the local file path. The public path prefix is stripped from the URL, and the unsecaped path suffix is appended to the outputPath: https://github.com/webpack/webpack-dev-middleware/blob/7ed24e0b9f53ad1562343f9f517f0f0ad2a70377/src/utils/getFilenameFromUrl.js#L82 As the URL is not unescaped and normalized automatically before calling the midlleware, it is possible to use %2e and %2f sequences to perform path traversal attack.
A blank project can be created containing the following configuration file webpack.config.js:
module.exports = { devServer: { devMiddleware: { writeToDisk: true } } };
When started, it is possible to access any local file, e.g. /etc/passwd:
$ curl localhost:8080/public/..%2f..%2f..%2f..%2f../etc/passwd
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
The developers using webpack-dev-server or webpack-dev-middleware are affected by the issue. When the project is started, an attacker might access any file on the developer's machine and exfiltrate the content (e.g. password, configuration files, private source code, ...).
If the development server is listening on a public IP address (or 0.0.0.0), an attacker on the local network can access the local files without any interaction from the victim (direct connection to the port).
If the server allows access from third-party domains (CORS, Allow-Access-Origin: * ), an attacker can send a malicious link to the victim. When visited, the client side script can connect to the local server and exfiltrate the local files.
The URL should be unescaped and normalized before any further processing.