CWE-637 保护机制不必要的复杂性（未使用经济性的机制）

Unnecessary Complexity in Protection Mechanism (Not Using 'Economy of Mechanism')

结构: Simple

Abstraction: Class

状态: Draft

被利用可能性: unkown

基本描述

The software uses a more complex mechanism than necessary, which could lead to resultant weaknesses when the mechanism is not correctly understood, modeled, configured, implemented, or used.

扩展描述

Security mechanisms should be as simple as possible. Complex security mechanisms may engender partial implementations and compatibility problems, with resulting mismatches in assumptions and implemented security. A corollary of this principle is that data specifications should be as simple as possible, because complex data specifications result in complex validation code. Complex tasks and systems may also need to be guarded by complex security checks, so simple systems should be preferred.

适用平台

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

常见的影响

范围	影响	注释
Other	Other

可能的缓解方案

Architecture and Design

策略:

Avoid complex security mechanisms when simpler ones would meet requirements. Avoid complex data models, and unnecessarily complex operations. Adopt architectures that provide guarantees, simplify understanding through elegance and abstraction, and that can be implemented similarly. Modularize, isolate and do not trust complex code, and apply other secure programming principles on these modules (e.g., least privilege) to mitigate vulnerabilities.

示例代码

例

The IPSEC specification is complex, which resulted in bugs, partial implementations, and incompatibilities between vendors.

例

HTTP Request Smuggling (CWE-444) attacks are feasible because there are not stringent requirements for how illegal or inconsistent HTTP headers should be handled. This can lead to inconsistent implementations in which a proxy or firewall interprets the same data stream as a different set of requests than the end points in that stream.

分析过的案例

标识	说明	链接
CVE-2007-6067	Support for complex regular expressions leads to a resultant algorithmic complexity weakness (CWE-407).	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-6067
CVE-2007-1552	Either a filename extension and a Content-Type header could be used to infer the file type, but the developer only checks the Content-Type, enabling unrestricted file upload (CWE-434).	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-1552
CVE-2007-6479	In Apache environments, a "filename.php.gif" can be redirected to the PHP interpreter instead of being sent as an image/gif directly to the user. Not knowing this, the developer only checks the last extension of a submitted filename, enabling arbitrary code execution.	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-6479
CVE-2005-2148	The developer cleanses the $_REQUEST superglobal array, but PHP also populates $_GET, allowing attackers to bypass the protection mechanism and conduct SQL injection attacks against code that uses $_GET.	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2005-2148

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