@saltcorn/server arbitrary file and directory listing when accessing build mobile app results

Summary

A user with admin permission can read arbitrary file and directory names on the filesystem by calling the admin/build-mobile-app/result?build_dir_name= endpoint. The build_dir_name parameter is not properly validated and it's then used to construct the buildDir that is read. The file/directory names under the buildDir will be returned.

Details

• file: https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/server/routes/admin.js#L2884-L2893

router.get(
  "/build-mobile-app/result",
  isAdmin,
  error_catcher(async (req, res) => {
    const { build_dir_name } = req.query; // [1] source
    const rootFolder = await File.rootFolder();
    const buildDir = path.join(
      rootFolder.location,
      "mobile_app",
      build_dir_name // [2]
    );
    const files = await Promise.all(
      fs
        .readdirSync(buildDir) // [3] sink
        .map(async (outFile) => await File.from_file_on_disk(outFile, buildDir))
    );
    [...]
  })
);

PoC

• log into the application as an admin user
• visit the following url: http://localhost:3000/admin/build-mobile-app/result?build_dir_name=/../../../../../../../../

NOTE: it's possible to only see file and directory names but not to download their content.

Impact

Information disclosure

Recommended Mitigation

Resolve the buildDir and check if it starts with ${rootFolder.location}/mobile_app.