How it was found

I would like to report n uninitialized Buffer allocation issue in stringstream. It allows to extract sensitive data from uninitialized memory or to cause a DoS by passing in a large number, in setups where typed user input can be passed to the stream (e.g. from JSON), on Node.js 4.x and lower.

Module

module name: stringstream version: 0.0.5 npm page: https://www.npmjs.com/package/stringstream

Module Description

Decode streams into strings The Right Way(tm)

Module Stats

740 368 downloads in the last day 4 606 368 downloads in the last week 19 182 466 downloads in the last month

Vulnerability

Vulnerability Description

See https://github.com/mhart/StringStream/blob/v0.0.5/stringstream.js#L32

The problem arises when a number is passed in the stream. That is unlikely to be attacker-controlled in real-world setups, but still possible. The API should not propagate the already-bad Buffer issue further.

On Node.js 4.x and below (4.x is still supported), this exposes uninitialized memory, which could contain sensitive data.

On Node.js 6.x and newer, this is type-checked on Node.js side and thows an error there.

Steps To Reproduce:

var stringstream = require('stringstream')
var stream = stringstream('hex', 'utf8')
stream.pipe(process.stdout)
stream.write(10000);
stream.end();

Run on Node.js 4.x (or lower). hex/utf8 is irrelevant, the issue is reproducable with all encodings.

Supporting Material/References:

• Arch Linux Current
• Node.js 4.8.7

Wrap up

• I contacted the maintainer to let them know: N
• I opened an issue in the related repository: N

Impact

Sensitive uninitialized memory exposure Denail of Service This issue affects only setups using Node.js 4.x (still supported) or lower.