Common Weakness Enumeration

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CWE-1241: Use of Predictable Algorithm in Random Number Generator

Weakness ID: 1241
Abstraction: Base
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
The product requires a true random number but uses an algorithm that is predictable and generates a pseudo-random number.
+ Relationships

The table(s) below shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.

+ Relevant to the view "Research Concepts" (CWE-1000)
ChildOfClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.330Use of Insufficiently Random Values
+ Relevant to the view "Software Development" (CWE-699)
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1213Random Number Issues
+ Relevant to the view "Hardware Design" (CWE-1194)
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1205Security Primitives and Cryptography Issues
+ Modes Of Introduction

The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

Architecture and DesignThis weakness is primarily introduced during the architecture and design phase when an incorrect algorithm is defined.
ImplementationIn many cases, the design originally defines a proper cryptography primitive, but this is then changed during implementation due to unforseen constraints.
+ Applicable Platforms
The listings below show possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.


Class: System on Chip (Undetermined Prevalence)

+ Common Consequences

The table below specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.


Technical Impact: Read Application Data

Predictable random numbers can render the protection mechanisms in place ineffective.
+ Demonstrative Examples

Example 1

Suppose a cryptographic function expects to begin with a random seed.

During the implementation phase, due to space constraint, a proper random-number-generator could not be used, and instead of using a TRNG (True Random Number Generator), the designer uses a LFSR (Linear Feedback Shift Register)to generate the seed. While an LFSR does provide pseudo-random number generation service, its entropy (measure of randomness) is less than that of a TRNG. Thus, using an LFSR weakens the strength of the crypto.This lack of entropy would weaken the overall crypto.

+ Potential Mitigations

Phase: Architecture and Design

Leverage well-known true random number generation techniques.

Effectiveness: High

+ Content History
+ Submissions
Submission DateSubmitterOrganization
2020-02-10Arun Kanuparthi, Hareesh Khattri, Parbati Kumar Manna, Narasimha Kumar V MangipudiIntel Corporation
+ Modifications
Modification DateModifierOrganization
2020-06-25CWE Content TeamMITRE
updated Common_Consequences, Demonstrative_Examples, Modes_of_Introduction
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Page Last Updated: June 25, 2020