CWE-578 EJB不安全实践：使用类加载器

EJB Bad Practices: Use of Class Loader

结构: Simple

Abstraction: Variant

状态: Draft

被利用可能性: unkown

基本描述

The program violates the Enterprise JavaBeans (EJB) specification by using the class loader.

扩展描述

The Enterprise JavaBeans specification requires that every bean provider follow a set of programming guidelines designed to ensure that the bean will be portable and behave consistently in any EJB container. In this case, the program violates the following EJB guideline: "The enterprise bean must not attempt to create a class loader; obtain the current class loader; set the context class loader; set security manager; create a new security manager; stop the JVM; or change the input, output, and error streams." The specification justifies this requirement in the following way: "These functions are reserved for the EJB container. Allowing the enterprise bean to use these functions could compromise security and decrease the container's ability to properly manage the runtime environment."

相关缺陷

  • cwe_Nature: ChildOf cwe_CWE_ID: 573 cwe_View_ID: 1000 cwe_Ordinal: Primary

  • cwe_Nature: ChildOf cwe_CWE_ID: 573 cwe_View_ID: 699 cwe_Ordinal: Primary

适用平台

Language: {'cwe_Name': 'Java', 'cwe_Prevalence': 'Undetermined'}

常见的影响

范围 影响 注释
['Confidentiality', 'Integrity', 'Availability', 'Other'] ['Execute Unauthorized Code or Commands', 'Varies by Context']

可能的缓解方案

['Architecture and Design', 'Implementation']

策略:

Do not use the Class Loader when writing EJBs.

示例代码

例

The following Java example is a simple stateless Enterprise JavaBean that retrieves the interest rate for the number of points for a mortgage. The interest rates for various points are retrieved from an XML document on the local file system, and the EJB uses the Class Loader for the EJB class to obtain the XML document from the local file system as an input stream.

bad Java

@Stateless
public class InterestRateBean implements InterestRateRemote {
private Document interestRateXMLDocument = null;

public InterestRateBean() {
try {

// get XML document from the local filesystem as an input stream

// using the ClassLoader for this class
ClassLoader loader = this.getClass().getClassLoader();
InputStream in = loader.getResourceAsStream(Constants.INTEREST_RATE_FILE);


DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
interestRateXMLDocument = db.parse(interestRateFile);
} catch (IOException ex) {...}
}
public BigDecimal getInterestRate(Integer points) {
return getInterestRateFromXML(points);
}

/ member function to retrieve interest rate from XML document on the local file system /

private BigDecimal getInterestRateFromXML(Integer points) {...}
}

This use of the Java Class Loader class within any kind of Enterprise JavaBean violates the restriction of the EJB specification against obtaining the current class loader as this could compromise the security of the application using the EJB.

例

An EJB is also restricted from creating a custom class loader and creating a class and instance of a class from the class loader, as shown in the following example.

bad Java

@Stateless
public class LoaderSessionBean implements LoaderSessionRemote {
public LoaderSessionBean() {
try {
ClassLoader loader = new CustomClassLoader();
Class c = loader.loadClass("someClass");
Object obj = c.newInstance();
/ perform some task that uses the new class instance member variables or functions /
...
} catch (Exception ex) {...}
}

public class CustomClassLoader extends ClassLoader {

}
}

分类映射

映射的分类名 ImNode ID Fit Mapped Node Name
Software Fault Patterns SFP3 Use of an improper API