CWE Reference

CWE-330: Use of Insufficiently Random Values

Official CWE-330 CWE context with Glexia analysis, remediation guidance, related CVEs, and ATT&CK context.

Release 4.20weaknessStable

Glexia's Take

CWE-330: Use of Insufficiently Random Values

Use of Insufficiently Random Values represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Executive Impact

Confidentiality,Other: Other: When a protection mechanism relies on random values to restrict access to a sensitive resource, such as a session ID or a seed for generating a cryptographic key, then the resource being protected could be accessed by guessing the ID or key.
Access Control,Other: Bypass Protection Mechanism,Other: If product relies on unique, unguessable IDs to identify a resource, an attacker might be able to guess an ID for a resource that is owned by another user. The attacker could then read the resource, or pre-create a resource with the same ID to prevent the legitimate program from properly sending the resource to the intended user. For example, a product might maintain session information in a file whose name is based on a username. An attacker could pre-create this file for a victim user, then set the permissions so that the application cannot generate the session for the victim, preventing the victim from using the application.
Access Control: Bypass Protection Mechanism,Gain Privileges or Assume Identity: When an authorization or authentication mechanism relies on random values to restrict access to restricted functionality, such as a session ID or a seed for generating a cryptographic key, then an attacker may access the restricted functionality by guessing the ID or key.

Developer Pattern

CWE-330 is the kind of defect developers can usually prevent with explicit validation, safer framework defaults, and tests that exercise hostile input or unsafe state transitions.

Confidence

high confidence from CWE-330, 4.20.

Official CWE Definition

CWE-330: Use of Insufficiently Random Values

The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.

Type: weakness
Abstraction: Class
Status: Stable
Source: MITRE CWE definition

Developer And Remediation Guidance

How teams prevent and detect this weakness

Causes

This code attempts to generate a unique random identifier for a user's session. Because the seed for the PRNG is always the user's ID, the session ID will always be the same. An attacker could thus predict any user's session ID and potentially hijack the session.,This example also exhibits a Small Seed Space (CWE-339).
The following code uses a statistical PRNG to create a URL for a receipt that remains active for some period of time after a purchase. This code uses the Random.nextInt() function to generate "unique" identifiers for the receipt pages it generates. Because Random.nextInt() is a statistical PRNG, it is easy for an attacker to guess the strings it generates. Although the underlying design of the receipt system is also faulty, it would be more secure if it used a random number generator that did not produce predictable receipt identifiers, such as a cryptographic PRNG.

Remediation

Architecture and Design: [object Object]
Implementation: Consider a PRNG that re-seeds itself as needed from high quality pseudo-random output sources, such as hardware devices.
Architecture and Design,Requirements: Use products or modules that conform to FIPS 140-2 [REF-267] to avoid obvious entropy problems. Consult FIPS 140-2 Annex C ("Approved Random Number Generators").

Detection

Black Box: [object Object]
Automated Static Analysis - Binary or Bytecode: [object Object]
Manual Static Analysis - Binary or Bytecode: [object Object]
Dynamic Analysis with Manual Results Interpretation: [object Object]
Manual Static Analysis - Source Code: [object Object]
Automated Static Analysis - Source Code: [object Object]
Architecture or Design Review: [object Object]

Mappings

Related CVEs, CWEs, and ATT&CK context

Related CWEs

Related CVEs

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ATT&CK Relevance

ATT&CK relevance is shown only when reviewed or responsibly inferred.