如何修复 java 中的“禁用 XML 外部实体 (XXE) 处理”漏洞

Question

我针对 sonarqube 运行我的 java 代码，我得到了“禁用 XML 外部实体 (XXE) 处理”作为漏洞。我花了一些时间在谷歌上解决这个问题。我一直在尝试很多方法，但没有任何方法适合我。我不知道我错过了什么我的代码：        final DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();        docFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);        docFactory.setFeature(XMLInputFactory.IS_SUPPORTING_EXTERNAL_ENTITIES, false);        docFactory.setFeature(XMLInputFactory.SUPPORT_DTD, false);        docFactory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);        docFactory.setFeature("http://xml.org/sax/features/external-general-entities", false);        docFactory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);        docFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);        final DocumentBuilder docBuilder = docFactory.newDocumentBuilder();        final Document doc = docBuilder.parse(filepath);我正在使用 java 1.8，感谢任何帮助。谢谢

Answer 1

我最终添加了以下所有属性，以避免 Sonar 抱怨此漏洞：

        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

        //REDHAT

        //https://www.blackhat.com/docs/us-15/materials/us-15-Wang-FileCry-The-New-Age-Of-XXE-java-wp.pdf

        factory.setAttribute(XMLConstants.FEATURE_SECURE_PROCESSING, true);

        factory.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");

        factory.setAttribute(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");

        //OWASP

        //https://cheatsheetseries.owasp.org/cheatsheets/XML_External_Entity_Prevention_Cheat_Sheet.html

        factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);

        factory.setFeature("http://xml.org/sax/features/external-general-entities", false);

        factory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);

        // Disable external DTDs as well

        factory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);

        // and these as well, per Timothy Morgan's 2014 paper: "XML Schema, DTD, and Entity Attacks"

        factory.setXIncludeAware(false);

        factory.setExpandEntityReferences(false);

        DocumentBuilder builder = factory.newDocumentBuilder();

Answer 2

Java 9+ 解决方案：

对我来说，更改DocumentBuilderFactory.newInstance()为DocumentBuilderFactory.newDefaultInstance()足以消除此警告。

Answer 3

只需设置这两个属性就足够了：

factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
factory.setFeature("http://xml.org/sax/features/external-general-entities", false);

Answer 4

我通过添加以下代码片段解决了这个问题：

saxParserFactory = SAXParserFactory.newInstance();

saxParserFactory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);

saxParserFactory.setFeature("http://xml.org/sax/features/external-general-entities", false);

saxParserFactory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);    

saxParserFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);

saxParserFactory.setXIncludeAware(false);