如何修复Java中的“禁用XML外部实体（XXE）处理”漏洞

java xml owasp sonarqube

2022-09-03 13:09:56

我针对sonarqube运行了我的Java代码，并且我得到了“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来解决这个问题。我一直在尝试很多方法，但没有任何东西对我有用。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，任何帮助都是值得赞赏的。谢谢

答案 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();

答案 2

只需设置以下两个属性就足够了：

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