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Added XEE Protection features (that were missing according to Stackoverflow)

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This commit is contained in:
Dominik Röschke
2025-03-18 08:43:00 +01:00
parent 5e511acf3c
commit 8127b177fb
4 changed files with 56 additions and 13 deletions
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18
validator/src/main/java/org/mustangproject/validator/XMLValidator.java
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@@ -150,13 +150,23 @@ public class XMLValidator extends Validator {
*/
final DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(true); // otherwise we can not act namespace independently, i.e. use
// document.getElementsByTagNameNS("*",...
dbf.setExpandEntityReferences(false);
dbf.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
//REDHAT
//https://www.blackhat.com/docs/us-15/materials/us-15-Wang-FileCry-The-New-Age-Of-XXE-java-wp.pdf
dbf.setAttribute(XMLConstants.FEATURE_SECURE_PROCESSING, true);
dbf.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
dbf.setAttribute(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");
//OWASP
//https://cheatsheetseries.owasp.org/cheatsheets/XML_External_Entity_Prevention_Cheat_Sheet.html
dbf.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
dbf.setFeature("http://xml.org/sax/features/external-general-entities", false);
dbf.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
// Disable external DTDs as well
dbf.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"
dbf.setXIncludeAware(false);
dbf.setExpandEntityReferences(false);
dbf.setNamespaceAware(true);
final DocumentBuilder db = dbf.newDocumentBuilder();
final InputSource is = new InputSource(new StringReader(zfXML));

17
validator/src/main/java/org/mustangproject/validator/ZUGFeRDValidator.java
View File

@@ -143,12 +143,23 @@ public class ZUGFeRDValidator {
String xmlAsString = null;
try {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(true);
dbf.setExpandEntityReferences(false);
dbf.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
//REDHAT
//https://www.blackhat.com/docs/us-15/materials/us-15-Wang-FileCry-The-New-Age-Of-XXE-java-wp.pdf
dbf.setAttribute(XMLConstants.FEATURE_SECURE_PROCESSING, true);
dbf.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
dbf.setAttribute(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");
//OWASP
//https://cheatsheetseries.owasp.org/cheatsheets/XML_External_Entity_Prevention_Cheat_Sheet.html
dbf.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
dbf.setFeature("http://xml.org/sax/features/external-general-entities", false);
dbf.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
// Disable external DTDs as well
dbf.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"
dbf.setXIncludeAware(false);
dbf.setExpandEntityReferences(false);
dbf.setNamespaceAware(true);
DocumentBuilder db = dbf.newDocumentBuilder();
content = XMLTools.removeBOM(content);