CWE-182 数据的崩溃导致不安全数值

Collapse of Data into Unsafe Value

结构: Simple

Abstraction: Base

状态: Draft

被利用可能性: unkown

基本描述

The software filters data in a way that causes it to be reduced or "collapsed" into an unsafe value that violates an expected security property.

相关缺陷

• cwe_Nature: ChildOf cwe_CWE_ID: 693 cwe_View_ID: 1000 cwe_Ordinal: Primary

• cwe_Nature: CanPrecede cwe_CWE_ID: 33 cwe_View_ID: 1000

• cwe_Nature: CanPrecede cwe_CWE_ID: 34 cwe_View_ID: 1000

• cwe_Nature: CanPrecede cwe_CWE_ID: 35 cwe_View_ID: 1000

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	Bypass Protection Mechanism

可能的缓解方案

MIT-44 Architecture and Design

策略: Input Validation

Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.

MIT-5 Implementation

策略: Input Validation

Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a whitelist of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
Do not rely exclusively on looking for malicious or malformed inputs (i.e., do not rely on a blacklist). A blacklist is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, blacklists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

MIT-20 Implementation

策略: Input Validation

Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass whitelist validation schemes by introducing dangerous inputs after they have been checked.

策略:

Canonicalize the name to match that of the file system's representation of the name. This can sometimes be achieved with an available API (e.g. in Win32 the GetFullPathName function).

分析过的案例

标识	说明	链接
CVE-2004-0815	"/.////" in pathname collapses to absolute path.	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-0815
CVE-2005-3123	"/.//..//////././" is collapsed into "/.././" after ".." and "//" sequences are removed.	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2005-3123
CVE-2002-0325	".../...//" collapsed to "..." due to removal of "./" in web server.	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2002-0325
CVE-2002-0784	chain: HTTP server protects against ".." but allows "." variants such as "////./../.../". If the server removes "/.." sequences, the result would collapse into an unsafe value "////../" (CWE-182).	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2002-0784
CVE-2005-2169	MFV. Regular expression intended to protect against directory traversal reduces ".../...//" to "../".	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2005-2169
CVE-2001-1157	XSS protection mechanism strips a	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2001-1157

Notes

分类映射

映射的分类名	ImNode ID	Fit	Mapped Node Name
PLOVER			Collapse of Data into Unsafe Value
The CERT Oracle Secure Coding Standard for Java (2011)	IDS11-J		Eliminate noncharacter code points before validation

引用

• REF-62 The Art of Software Security Assessment

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