Improper Handling of Insufficient Entropy in TRNG

Opis

True 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.

Skutki

• Availability

  DoS: Crash, Exit, or Restart

  A program may crash or block if it runs out of random numbers.

Zapobieganie

• Implementation

  Rather than failing on a lack of random numbers, it is often preferable to wait for more numbers to be created.

Słabość nadrzędna

• CWE-331 Insufficient Entropy
• CWE-755 Improper Handling of Exceptional Conditions

Kiedy powstaje

• Architecture and Design
• Implementation — REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Dotyczy

Not Language-Specific

Uwagi

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.

Źródła

1. The CLASP Application Security Process — Secure Software, Inc., 2005