CWE-334 随机数的空间太小

Small Space of Random Values

结构: Simple

Abstraction: Base

状态: Draft

被利用可能性: unkown

基本描述

The number of possible random values is smaller than needed by the product, making it more susceptible to brute force attacks.

相关缺陷

• cwe_Nature: ChildOf cwe_CWE_ID: 330 cwe_View_ID: 1000 cwe_Ordinal: Primary

• cwe_Nature: ChildOf cwe_CWE_ID: 330 cwe_View_ID: 699 cwe_Ordinal: Primary

适用平台

Language: {'cwe_Class': 'Language-Independent', 'cwe_Prevalence': 'Undetermined'}

常见的影响

范围	影响	注释
['Access Control', 'Other']	['Bypass Protection Mechanism', 'Other']	An attacker could easily guess the values used. This could lead to unauthorized access to a system if the seed is used for authentication and authorization.

可能的缓解方案

MIT-2 ['Architecture and Design', 'Requirements']

策略: Libraries or Frameworks

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").

示例代码

例

The following XML example code is a deployment descriptor for a Java web application deployed on a Sun Java Application Server. This deployment descriptor includes a session configuration property for configuring the session ID length.

bad XML

This deployment descriptor has set the session ID length for this Java web application to 8 bytes (or 64 bits). The session ID length for Java web applications should be set to 16 bytes (128 bits) to prevent attackers from guessing and/or stealing a session ID and taking over a user's session.

Note for most application servers including the Sun Java Application Server the session ID length is by default set to 128 bits and should not be changed. And for many application servers the session ID length cannot be changed from this default setting. Check your application server documentation for the session ID length default setting and configuration options to ensure that the session ID length is set to 128 bits.

分析过的案例

标识	说明	链接
CVE-2002-0583	Product uses 5 alphanumeric characters for filenames of expense claim reports, stored under web root.	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2002-0583
CVE-2002-0903	Product uses small number of random numbers for a code to approve an action, and also uses predictable new user IDs, allowing attackers to hijack new accounts.	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2002-0903
CVE-2003-1230	SYN cookies implementation only uses 32-bit keys, making it easier to brute force ISN.	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2003-1230
CVE-2004-0230	Complex predictability / randomness (reduced space).	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-0230

分类映射

映射的分类名	ImNode ID	Fit	Mapped Node Name
PLOVER			Small Space of Random Values

引用

• REF-267 SECURITY REQUIREMENTS FOR CRYPTOGRAPHIC MODULES

• REF-44 24 Deadly Sins of Software Security

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