CWE

Predictable Seed in PRNG

ID: 337		Date: (C)2012-05-14   (M)2022-10-10
Type: weakness		Status: DRAFT
Abstraction Type: Base

Description

A PRNG is initialized from a predictable seed, e.g. using process ID or system time.

Applicable Platforms
Language Class: All

Time Of Introduction

• Architecture and Design
• Implementation

Common Consequences

Scope	Technical Impact	Notes
Other	Varies by context

Detection Methods
None

Potential Mitigations

Phase	Strategy	Description	Effectiveness	Notes
		Use non-predictable inputs for seed generation.
Architecture and Design Requirements	Libraries or Frameworks	Use products or modules that conform to FIPS 140-2 [R.337.1] to avoid obvious entropy problems. Consult FIPS 140-2 Annex C ("Approved Random Number Generators").
Implementation		Use a PRNG that periodically re-seeds itself using input from high-quality sources, such as hardware devices with high entropy. However, do not re-seed too frequently, or else the entropy source might block.

Relationships

Related CWE	Type	View	Chain
CWE-337 ChildOf CWE-905	Category	CWE-888

Demonstrative Examples   (Details)

1. Both of these examples use a statistical PRNG seeded with the current value of the system clock to generate a random number: (Demonstrative Example Id DX-102)

White Box Definitions
None

Black Box Definitions
None

Taxynomy Mappings

Taxynomy	Id	Name	Fit
PLOVER		Predictable 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.
2. Michael Howard David LeBlanc John Viega .24 Deadly Sins of Software Security. McGraw-Hill. Section:'"Sin 20: Weak Random Numbers." Page 299'. Published on 2010.