CWE

Same Seed in PRNG

ID: 336		Date: (C)2012-05-14   (M)2022-10-10
Type: weakness		Status: DRAFT
Abstraction Type: Base

Description

A PRNG uses the same seed each time the product is initialized. If an attacker can guess (or knows) the seed, then he/she may be able to determine the "random" number produced from the PRNG.

Applicable Platforms
Language Class: All

Time Of Introduction

• Architecture and Design
• Implementation

Common Consequences

Scope	Technical Impact	Notes
Other Access_Control	Other Bypass protection mechanism

Detection Methods
None

Potential Mitigations

Phase	Strategy	Description	Effectiveness	Notes
Architecture and Design		Do not reuse PRNG seeds. Consider a PRNG that periodically re-seeds itself as needed from a high quality pseudo-random output, such as hardware devices.
Architecture and Design Requirements	Libraries or Frameworks	Use products or modules that conform to FIPS 140-2 [R.336.1] to avoid obvious entropy problems. Consult FIPS 140-2 Annex C ("Approved Random Number Generators").

Relationships

Related CWE	Type	View	Chain
CWE-336 ChildOf CWE-905	Category	CWE-888

Demonstrative Examples   (Details)

1. The following Java code uses the same seed value for a statistical PRNG on every invocation.

White Box Definitions
None

Black Box Definitions
None

Taxynomy Mappings

Taxynomy	Id	Name	Fit
PLOVER		Same Seed in PRNG
CERT Java Secure Coding	MSC02-J	Generate strong random numbers

References:

1. Information Technology Laboratory, National Institute of Standards and Technology .SECURITY REQUIREMENTS FOR CRYPTOGRAPHIC MODULES. 2001-05-25.