Difference between revisions of "Insufficient Entropy"

Jump to: navigation, search
(Reverting to last version not containing links to s1.shard.jp)
(8 intermediate revisions by 2 users not shown)
(No difference)

Revision as of 06:50, 3 June 2009

This article is a stub. You can help OWASP by expanding it or discussing it on its Talk page.

This is a Vulnerability. To view all vulnerabilities, please see the Vulnerability Category page.

Last revision (mm/dd/yy): 06/3/2009

Vulnerabilities Table of Contents


When an undesirably low amount of entropy is available. Psuedo Random Number Generators are susceptible to suffering from insufficient entropy when they are initialized, because entropy data may not be available to them yet.

Risk Factors




Related Attacks

  • In many case,s a PRNG uses a combination of the system clock and entropy to create seed data. If insufficient entropy is available, an attacker can reduce the size magnitude of the seed value considerably. Furthermore, by guessing values of the system clock, they can create a manageable set of possible PRNG outputs.

Related Vulnerabilities

Related Controls

  • Many PRNG's (/dev/random and /dev/urandom for example) store their last value before shutdown. By using this value at intialization, they can sometimes avoid insufficient or predictable starting entropy.

Related Technical Impacts