名前: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.

一般情報

導入モード

Architecture and Design
Implementation : REALIZATION: This weakness is caused during implementation of an architectural security tactic.

適用可能なプラットフォーム

言語

クラス： Not Language-Specific (Undetermined)

テクノロジー

クラス： Not Technology-Specific (Undetermined)

一般的な結果

スコープ	影響	可能性
Access Control	Bypass Protection Mechanism 注記：If a PRNG is used for authentication and authorization, such as a session ID or a seed for generating a cryptographic key, then an attacker may be able to easily guess the ID or cryptographic key and gain access to restricted functionality.

観察された例

参考文献	説明
CVE-2021-3692	PHP framework uses mt_rand() function (Marsenne Twister) when generating tokens
CVE-2009-3278	Crypto product uses rand() library function to generate a recovery key, making it easier to conduct brute force attacks.
CVE-2009-3238	Random number generator can repeatedly generate the same value.
CVE-2009-2367	Web application generates predictable session IDs, allowing session hijacking.
CVE-2008-0166	SSL library uses a weak random number generator that only generates 65,536 unique keys.

潜在的な緩和策

Phases : Implementation
Use functions or hardware which use a hardware-based random number generation for all crypto. This is the recommended solution. Use CyptGenRandom on Windows, or hw_rand() on Linux.

検出方法

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
有効性 : High

脆弱性マッピングノート

理由 : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
コメント : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

ノート

As of CWE 4.5, terminology related to randomness, entropy, and predictability can vary widely. Within the developer and other communities, "randomness" is used heavily. However, within cryptography, "entropy" is distinct, typically implied as a measurement. There are no commonly-used definitions, even within standards documents and cryptography papers. Future versions of CWE will attempt to define these terms and, if necessary, distinguish between them in ways that are appropriate for different communities but do not reduce the usability of CWE for mapping, understanding, or other scenarios.

参考文献

REF-18

The CLASP Application Security Process
Secure Software, Inc..
https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf

REF-44

24 Deadly Sins of Software Security
Michael Howard, David LeBlanc, John Viega.

登録情報

名前	組織	日付	リリース日	Version
CLASP		2006-07-19 +00:00	2006-07-19 +00:00	Draft 3

変更履歴

名前	組織	日付	コメント
Eric Dalci	Cigital	2008-07-01 +00:00	updated Time_of_Introduction
CWE Content Team	MITRE	2008-09-08 +00:00	updated Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings
CWE Content Team	MITRE	2011-06-01 +00:00	updated Common_Consequences
CWE Content Team	MITRE	2012-05-11 +00:00	updated Common_Consequences, Observed_Examples, References, Relationships
CWE Content Team	MITRE	2012-10-30 +00:00	updated Demonstrative_Examples, Potential_Mitigations
CWE Content Team	MITRE	2014-06-23 +00:00	updated Applicable_Platforms, Description, Name, Other_Notes
CWE Content Team	MITRE	2015-12-07 +00:00	updated Relationships
CWE Content Team	MITRE	2017-11-08 +00:00	updated Demonstrative_Examples, Description, Modes_of_Introduction, Relationships, Taxonomy_Mappings
CWE Content Team	MITRE	2019-01-03 +00:00	updated Relationships
CWE Content Team	MITRE	2020-02-24 +00:00	updated References, Relationships
CWE Content Team	MITRE	2021-03-15 +00:00	updated Demonstrative_Examples
CWE Content Team	MITRE	2021-07-20 +00:00	updated Maintenance_Notes
CWE Content Team	MITRE	2021-10-28 +00:00	updated Relationships
CWE Content Team	MITRE	2023-04-27 +00:00	updated Detection_Factors, Relationships
CWE Content Team	MITRE	2023-06-29 +00:00	updated Mapping_Notes
CWE Content Team	MITRE	2023-10-26 +00:00	updated Observed_Examples
CWE Content Team	MITRE	2025-12-11 +00:00	updated Applicable_Platforms, Relationships, Weakness_Ordinalities

CWE-338 詳細

CWE-338