CWE-342: Predictable Exact Value from Previous Values
CWE版本: 4.18
更新日期: 2025-09-09
弱点描述
An exact value or random number can be precisely predicted by observing previous values.
常见后果
影响范围: Other
技术影响: Varies by Context
潜在缓解措施
描述: Increase the entropy used to seed a PRNG.
阶段: Architecture and Design Requirements
策略: Libraries or Frameworks
描述: 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").
阶段: Implementation
描述: 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.
观察示例
参考: CVE-2002-1463
Firewall generates easily predictable initial sequence numbers (ISN), which allows remote attackers to spoof connections.
参考: CVE-1999-0074
Listening TCP ports are sequentially allocated, allowing spoofing attacks.
参考: CVE-1999-0077
Predictable TCP sequence numbers allow spoofing.
参考: CVE-2000-0335
DNS resolver uses predictable IDs, allowing a local user to spoof DNS query results.
引入模式
| 阶段 | 说明 |
|---|---|
| Architecture and Design | - |
| Implementation | - |
适用平台
编程语言
分类映射
| 分类名称 | 条目ID | 条目名称 | 映射适配度 |
|---|---|---|---|
| PLOVER | - | Predictable Exact Value from Previous Values | - |