CVE-2017-12621: Apache Commons Jelly connects to URL with custom doctype definitions.
Severity: Medium Vendor: The Apache Software Foundation Versions Affected: commons-jelly-1.0 (core), namely commons-jelly-1.0.jar Description: During Jelly (xml) file parsing with Apache Xerces, if a custom doctype entity is declared with a “SYSTEM” entity with a URL and that entity is used in the body of the Jelly file, during parser instantiation the parser will attempt to connect to said URL. This could lead to XML External Entity (XXE) attacks. The Open Web Application Security Project suggests that the fix be https://www.owasp.org/index.php/XML_External_Entity_(XXE)_Prevention_Cheat_Sheet#XMLReader Mitigation: 1.0 users should migrate to 1.0.1. Example: example.jelly -------------- <?xml version="1.0"?> <!--- Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. --> <!DOCTYPE r [ <!ELEMENT r ANY > <!ENTITY sp SYSTEM "http://127.0.0.1:4444/";> ]> <r>&sp;</r> <j:jelly trim="false" xmlns:j="jelly:core" xmlns:x="jelly:xml" xmlns:html="jelly:html"> </j:jelly> -------------- ExampleParser.java ------------------ public class ExampleParser { public static void main(String[] args) throws JellyException, IOException, NoSuchMethodException, IllegalAccessException,IllegalArgumentException, InvocationTargetException { JellyContext context = new JellyContext(); context.runScript("example.jelly", null); } } Credit: This was discovered by Luca Carettoni of Doyensec. References: [1] http://commons.apache.org/jelly/security-reports.html [2] https://issues.apache.org/jira/browse/JELLY-293 --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org
