Cryptographic Issues

Affecting elliptic package, versions <6.5.3

Overview

elliptic is a Fast elliptic-curve cryptography in a plain javascript implementation.

Affected versions of this package are vulnerable to Cryptographic Issues. Elliptic allows ECDSA signature malleability via variations in encoding, leading \0 bytes, or integer overflows. This could conceivably have a security-relevant impact if an application relied on a single canonical signature.

PoC

var crypto = require('crypto')
var EC = require('elliptic').ec;
var ec = new EC('secp256k1');

var obj = require("./poc_ecdsa_secp256k1_sha256_test.json");

for (let testGroup of obj.testGroups) {

    var key = ec.keyFromPublic(testGroup.key.uncompressed, 'hex');
    
    for(let test of testGroup.tests) {
     console.log("[*] Test " + test.tcId + " result: " + test.result)

     msgHash = crypto.createHash('sha256').update(Buffer.from(test.msg, 'hex')).digest();
     
     try {
      result = key.verify(msgHash, Buffer.from(test.sig, 'hex'));

     if (result == true) {
      if (test.result == "valid" || test.result == "acceptable")
       console.log("Result: PASS");
      else
       console.log("Result: FAIL")     
     }

     if (result == false) {
      if (test.result == "valid" || test.result == "acceptable")
       console.log("Result: FAIL");
      else
       console.log("Result: PASS")     
     }



     } catch (e) {
      console.log("ERROR - VERIFY: " + e)

      if (test.result == "valid" || test.result == "acceptable")
       console.log("Result: FAIL");
      else
       console.log("Result: PASS")     



     }


    }

}

Remediation

Upgrade elliptic to version 6.5.3 or higher.

References

• Elliptic NPM Package
• GitHub Issue
• How Not To Use ECDSA
• Malleability Attack