The crypto-js package before 3.2.1 for Node.js generates random numbers by concatenating the string "0." with an integer, which makes the output more predictable than necessary.

crypto-js is a JavaScript library of crypto standards. Prior to version 4.2.0, crypto-js PBKDF2 is 1,000 times weaker than originally specified in 1993, and at least 1,300,000 times weaker than current industry standard. This is because it both defaults to SHA1, a cryptographic hash algorithm considered insecure since at least 2005, and defaults to one single iteration, a 'strength' or 'difficulty' value specified at 1,000 when specified in 1993. PBKDF2 relies on iteration count as a countermeasure to preimage and collision attacks. If used to protect passwords, the impact is high. If used to generate signatures, the impact is high. Version 4.2.0 contains a patch for this issue. As a workaround, configure crypto-js to use SHA256 with at least 250,000 iterations.