CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Description
The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.
Submission Date :
July 19, 2006, midnight
Modification Date :
2023-10-26 00:00:00+00:00
Organization :
MITRE
Extended Description
When a non-cryptographic PRNG is used in a cryptographic context, it can expose the cryptography to certain types of attacks.
Often a pseudo-random number generator (PRNG) is not designed for cryptography. Sometimes a mediocre source of randomness is sufficient or preferable for algorithms that use random numbers. Weak generators generally take less processing power and/or do not use the precious, finite, entropy sources on a system. While such PRNGs might have very useful features, these same features could be used to break the cryptography.
Example - 1
Both of these examples use a statistical PRNG seeded with the current value of the system clock to generate a random number: The random number functions used in these examples, rand() and Random.nextInt(), are not considered cryptographically strong. An attacker may be able to predict the random numbers generated by these functions. Note that these example also exhibit CWE-337 (Predictable Seed in PRNG).
Random random = new Random(System.currentTimeMillis());int accountID = random.nextInt();
srand(time());int randNum = rand();
Related Weaknesses
This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined to give an overview of the different insight to similar items that may exist at higher and lower levels of abstraction.
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