The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.

What CVEs are caused by CWE-330?

143 recorded CVEs are attributed to CWE-330, including CVE-2023-22601, CVE-2025-4607, CVE-2024-25943.

Is CWE-330 part of the OWASP Top 10?

CWE-330 maps to OWASP Top Ten 2004: Broken Access Control (A2) in the OWASP security taxonomy.

How do you prevent CWE-330?

Use a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations with adequate length seeds.

How is CWE-330 detected?

Black Box: Use monitoring tools that examine the software's process as it interacts with the operating system and the network. This technique is useful in cases when source code is unavailable, if the software was not developed by you, or if you want to verify that the build phase did not introduce any new weaknesses. Examples include debuggers that directly attach to the running process; system-call tracing utilities such as truss (Solaris) and strace (Linux); system activity monitors such as FileMon, RegMon, Process Monitor, and other Sysinternals utilities (Windows); and sniffers and protocol analyzers that monitor network traffic.

What are the consequences of CWE-330?

Exploiting CWE-330 can lead to: Other, Bypass Protection Mechanism, Gain Privileges or Assume Identity.

Is CWE-330 actively exploited?

143 recorded CVEs are caused by CWE-330; none are currently in CISA's KEV catalog of actively exploited flaws.

CWE-330: Use of Insufficiently Random Values

RadicalNotion.AI

Code examples

Illustrative examples from MITRE showing how the weakness appears in code.

This code attempts to generate a unique random identifier for a user's session.

Vulnerable example

php

function generateSessionID($userID){

The following code uses a statistical PRNG to create a URL for a receipt that remains active for some period of time after a purchase.

Vulnerable example

java

String GenerateReceiptURL(String baseUrl) {

This code uses the Random.nextInt() function to generate "unique" identifiers for the receipt pages it generates. Because Random.nextInt() is a statistical PRNG, it is easy for an attacker to guess the strings it generates. Although the underlying design of the receipt system is also faulty, it would be more secure if it used a random number generator that did not produce predictable receipt identifiers, such as a cryptographic PRNG.

Illustrative examples

Real CVEs that MITRE cites as examples of this weakness.

CVE-2021-3692 — PHP framework uses mt_rand() function (Marsenne Twister) when generating tokens
CVE-2020-7010 — Cloud application on Kubernetes generates passwords using a weak random number generator based on deployment time.
CVE-2009-3278 — Crypto product uses rand() library function to generate a recovery key, making it easier to conduct brute force attacks.
CVE-2009-3238 — Random number generator can repeatedly generate the same value.
CVE-2009-2367 — Web application generates predictable session IDs, allowing session hijacking.
CVE-2009-2158 — Password recovery utility generates a relatively small number of random passwords, simplifying brute force attacks.
CVE-2009-0255 — Cryptographic key created with a seed based on the system time.
CVE-2008-5162 — Kernel function does not have a good entropy source just after boot.
CVE-2008-4905 — Blogging software uses a hard-coded salt when calculating a password hash.
CVE-2008-4929 — Bulletin board application uses insufficiently random names for uploaded files, allowing other users to access private files.
CVE-2008-3612 — Handheld device uses predictable TCP sequence numbers, allowing spoofing or hijacking of TCP connections.
CVE-2008-2433 — Web management console generates session IDs based on the login time, making it easier to conduct session hijacking.
CVE-2008-0166 — SSL library uses a weak random number generator that only generates 65,536 unique keys.
CVE-2008-2108 — Chain: insufficient precision causes extra zero bits to be assigned, reducing entropy for an API function that generates random numbers.
CVE-2008-2108 — Chain: insufficient precision (CWE-1339) in random-number generator causes some zero bits to be reliably generated, reducing the amount of entropy (CWE-331)
CVE-2008-2020 — CAPTCHA implementation does not produce enough different images, allowing bypass using a database of all possible checksums.
CVE-2008-0087 — DNS client uses predictable DNS transaction IDs, allowing DNS spoofing.
CVE-2008-0141 — Application generates passwords that are based on the time of day.

CWE-330: Use of Insufficiently Random Values

Overview

Background

Real-world CVEs

Common consequences

How it happens

When it is introduced

How to prevent it

How to detect it

Black Box

Automated Static Analysis - Binary or Bytecode

Manual Static Analysis - Binary or Bytecode

Dynamic Analysis with Manual Results Interpretation

Manual Static Analysis - Source Code

Automated Static Analysis - Source Code

Architecture or Design Review

Code examples

Illustrative examples

Terminology & mappings

Mapped taxonomies

Attack patterns

Frequently asked questions

References

Stay ahead of CWE-330

Overview

Background

Real-world CVEs

Common consequences

How it happens

When it is introduced

How to prevent it

How to detect it

Black Box

Automated Static Analysis - Binary or Bytecode

Manual Static Analysis - Binary or Bytecode

Dynamic Analysis with Manual Results Interpretation

Manual Static Analysis - Source Code

Automated Static Analysis - Source Code

Architecture or Design Review

Code examples

Illustrative examples

Related weaknesses

Parent

Child

Can precede

Terminology & mappings

Mapped taxonomies

Attack patterns

Frequently asked questions

References

Stay ahead of CWE-330