Insecure Randomness Affecting crypto-browserify Open this link in a new tab package, versions <2.1.11

  • Attack Complexity


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  • snyk-id


  • published

    25 Dec 2017

  • disclosed

    21 Jul 2014

  • credit


Introduced: 21 Jul 2014

CWE-330 Open this link in a new tab


crypto-browserify is implementation of crypto for the browser.

Affected versions of the package are vulnerable to Insecure Randomness due to using the cryptographically insecure Math.random(). This function can produce predictable values and should not be used in security-sensitive context.


Computers are deterministic machines, and as such are unable to produce true randomness. Pseudo-Random Number Generators (PRNGs) approximate randomness algorithmically, starting with a seed from which subsequent values are calculated.

There are two types of PRNGs: statistical and cryptographic. Statistical PRNGs provide useful statistical properties, but their output is highly predictable and forms an easy to reproduce numeric stream that is unsuitable for use in cases where security depends on generated values being unpredictable. Cryptographic PRNGs address this problem by generating output that is more difficult to predict. For a value to be cryptographically secure, it must be impossible or highly improbable for an attacker to distinguish between it and a truly random value. In general, if a PRNG algorithm is not advertised as being cryptographically secure, then it is probably a statistical PRNG and should not be used in security-sensitive contexts.

You can read more about node's insecure Math.random() in Mike Malone's post.


Upgrade crypto-browserify to version 2.1.11 or higher.