119 lines
5.7 KiB
Plaintext
119 lines
5.7 KiB
Plaintext
include::../description.adoc[]
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== Noncompliant Code Example
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For https://docs.oracle.com/javase/9/docs/api/javax/xml/parsers/DocumentBuilderFactory.html[DocumentBuilder], https://docs.oracle.com/javase/9/docs/api/javax/xml/parsers/SAXParserFactory.html[SAXParser], https://docs.oracle.com/javase/9/docs/api/javax/xml/stream/XMLInputFactory.html[XMLInput], https://docs.oracle.com/javase/9/docs/api/javax/xml/transform/TransformerFactory.html[Transformer] and https://docs.oracle.com/javase/9/docs/api/javax/xml/validation/SchemaFactory.html[Schema] JAPX factories:
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----
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DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); // Noncompliant
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SAXParserFactory factory = SAXParserFactory.newInstance(); // Noncompliant
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XMLInputFactory factory = XMLInputFactory.newInstance(); // Noncompliant
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TransformerFactory factory = javax.xml.transform.TransformerFactory.newInstance(); // Noncompliant
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SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI); // Noncompliant
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----
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For https://dom4j.github.io/[Dom4j] library:
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----
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SAXReader xmlReader = new SAXReader(); // Noncompliant
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----
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For http://www.jdom.org/[Jdom2] library:
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----
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SAXBuilder builder = new SAXBuilder(); // Noncompliant
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----
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== Compliant Solution
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For https://docs.oracle.com/javase/9/docs/api/javax/xml/parsers/DocumentBuilderFactory.html[DocumentBuilder], https://docs.oracle.com/javase/9/docs/api/javax/xml/parsers/SAXParserFactory.html[SAXParser], https://docs.oracle.com/javase/9/docs/api/javax/xml/stream/XMLInputFactory.html[XMLInput], https://docs.oracle.com/javase/9/docs/api/javax/xml/transform/TransformerFactory.html[Transformer] and https://docs.oracle.com/javase/9/docs/api/javax/xml/validation/SchemaFactory.html[Schema] JAPX factories:
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----
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DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
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// to be compliant, completely disable DOCTYPE declaration:
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factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
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// or completely disable external entities declarations:
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factory.setFeature("http://xml.org/sax/features/external-general-entities", false);
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factory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
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// or prohibit the use of all protocols by external entities:
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factory.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
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factory.setAttribute(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");
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SAXParserFactory factory = SAXParserFactory.newInstance();
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// to be compliant, completely disable DOCTYPE declaration:
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factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
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// or completely disable external entities declarations:
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factory.setFeature("http://xml.org/sax/features/external-general-entities", false);
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factory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
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// or prohibit the use of all protocols by external entities:
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SAXParser parser = factory.newSAXParser(); // Noncompliant
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parser.setProperty(XMLConstants.ACCESS_EXTERNAL_DTD, "");
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parser.setProperty(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");
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XMLInputFactory factory = XMLInputFactory.newInstance();
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// to be compliant, completely disable DOCTYPE declaration:
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factory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
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// or completely disable external entities declarations:
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factory.setProperty(XMLInputFactory.IS_SUPPORTING_EXTERNAL_ENTITIES, Boolean.FALSE);
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// or prohibit the use of all protocols by external entities:
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factory.setProperty(XMLConstants.ACCESS_EXTERNAL_DTD, "");
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factory.setProperty(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");
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TransformerFactory factory = javax.xml.transform.TransformerFactory.newInstance();
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// to be compliant, prohibit the use of all protocols by external entities:
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factory.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
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factory.setAttribute(XMLConstants.ACCESS_EXTERNAL_STYLESHEET, "");
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SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
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// to be compliant, completely disable DOCTYPE declaration:
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factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
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// or prohibit the use of all protocols by external entities:
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factory.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
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factory.setAttribute(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");
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----
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For https://dom4j.github.io/[Dom4j] library:
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----
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SAXReader xmlReader = new SAXReader();
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xmlReader.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
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----
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For http://www.jdom.org/[Jdom2] library:
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----
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SAXBuilder builder = new SAXBuilder();
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builder.setProperty(XMLConstants.ACCESS_EXTERNAL_DTD, "");
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builder.setProperty(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");
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----
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== See
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* https://owasp.org/Top10/A05_2021-Security_Misconfiguration/[OWASP Top 10 2021 Category A5] - Security Misconfiguration
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* https://docs.oracle.com/en/java/javase/13/security/java-api-xml-processing-jaxp-security-guide.html#GUID-8CD65EF5-D113-4D5C-A564-B875C8625FAC[Oracle Java Documentation] - XML External Entity Injection Attack
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* https://www.owasp.org/index.php/Top_10-2017_A4-XML_External_Entities_(XXE)[OWASP Top 10 2017 Category A4] - XML External Entities (XXE)
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* https://cheatsheetseries.owasp.org/cheatsheets/XML_External_Entity_Prevention_Cheat_Sheet.html#java[OWASP XXE Prevention Cheat Sheet]
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* https://cwe.mitre.org/data/definitions/611.html[MITRE, CWE-611] - Information Exposure Through XML External Entity Reference
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* https://cwe.mitre.org/data/definitions/827.html[MITRE, CWE-827] - Improper Control of Document Type Definition
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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include::../message.adoc[]
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include::../highlighting.adoc[]
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'''
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== Comments And Links
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(visible only on this page)
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include::../comments-and-links.adoc[]
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endif::env-github,rspecator-view[]
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