CWE-333: Improper Handling of Insufficient Entropy in TRNG
View customized information:
For users who are interested in more notional aspects of a weakness. Example: educators, technical writers, and project/program managers.
For users who are concerned with the practical application and details about the nature of a weakness and how to prevent it from happening. Example: tool developers, security researchers, pen-testers, incident response analysts.
For users who are mapping an issue to CWE/CAPEC IDs, i.e., finding the most appropriate CWE for a specific issue (e.g., a CVE record). Example: tool developers, security researchers.
For users who wish to see all available information for the CWE/CAPEC entry.
For users who want to customize what details are displayed.
×
Edit Custom FilterTrue random number generators (TRNG) generally have a limited source of entropy and therefore can fail or block.
The rate at which true random numbers can be generated is limited. It is important that one uses them only when they are needed for security.
![]()
![]() ![]()
![]() ![]()
![]()
![]() Languages Class: Not Language-Specific (Undetermined Prevalence) Example 1 This code uses a TRNG to generate a unique session id for new connections to a server: (bad code)
Example Language: C
while (1){
if (haveNewConnection()){
if (hwRandom()){
int sessionID = hwRandom(); } } }createNewConnection(sessionID); This code does not attempt to limit the number of new connections or make sure the TRNG can successfully generate a new random number. An attacker may be able to create many new connections and exhaust the entropy of the TRNG. The TRNG may then block and cause the program to crash or hang. ![]()
Maintenance
As of CWE 4.5, terminology related to randomness, entropy, and
predictability can vary widely. Within the developer and other
communities, "randomness" is used heavily. However, within
cryptography, "entropy" is distinct, typically implied as a
measurement. There are no commonly-used definitions, even within
standards documents and cryptography papers. Future versions of
CWE will attempt to define these terms and, if necessary,
distinguish between them in ways that are appropriate for
different communities but do not reduce the usability of CWE for
mapping, understanding, or other scenarios.
More information is available — Please edit the custom filter or select a different filter. |
Use of the Common Weakness Enumeration (CWE™) and the associated references from this website are subject to the Terms of Use. CWE is sponsored by the U.S. Department of Homeland Security (DHS) Cybersecurity and Infrastructure Security Agency (CISA) and managed by the Homeland Security Systems Engineering and Development Institute (HSSEDI) which is operated by The MITRE Corporation (MITRE). Copyright © 2006–2025, The MITRE Corporation. CWE, CWSS, CWRAF, and the CWE logo are trademarks of The MITRE Corporation. |