CWE-112 XML验证缺失

Missing XML Validation

结构: Simple

Abstraction: Base

状态: Draft

被利用可能性: unkown

基本描述

The software accepts XML from an untrusted source but does not validate the XML against the proper schema.

扩展描述

Most successful attacks begin with a violation of the programmer's assumptions. By accepting an XML document without validating it against a DTD or XML schema, the programmer leaves a door open for attackers to provide unexpected, unreasonable, or malicious input.

适用平台

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

常见的影响

范围	影响	注释
Integrity	Unexpected State

可能的缓解方案

Architecture and Design

策略: Input Validation

Always validate XML input against a known XML Schema or DTD. It is not possible for an XML parser to validate all aspects of a document's content because a parser cannot understand the complete semantics of the data. However, a parser can do a complete and thorough job of checking the document's structure and therefore guarantee to the code that processes the document that the content is well-formed.

示例代码

例

The following code loads and parses an XML file.

bad Java

// Read DOM
try {

...
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating( false );
....
c_dom = factory.newDocumentBuilder().parse( xmlFile );

} catch(Exception ex) {

...

}

The XML file is loaded without validating it against a known XML Schema or DTD.

例

The following code creates a DocumentBuilder object to be used in building an XML document.

bad Java

DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
builderFactory.setNamespaceAware(true);
DocumentBuilder builder = builderFactory.newDocumentBuilder();

The DocumentBuilder object does not validate an XML document against a schema, making it possible to create an invalid XML document.

分类映射

映射的分类名	ImNode ID	Fit	Mapped Node Name
7 Pernicious Kingdoms			Missing XML Validation
Software Fault Patterns	SFP24		Tainted input to command

VULHUB ™