Ruby Entity expansion DoS vulnerability in REXML (XML bomb)

2013.03.07
Credit: Kurt Seifried
Risk: Medium
Local: No
Remote: Yes
CVE: N/A
CWE: CWE-776

http://www.ruby-lang.org/en/news/2013/02/22/rexml-dos-2013-02-22/ ===== Unrestricted entity expansion can lead to a DoS vulnerability in REXML. (The CVE identifier will be assigned later.) We strongly recommend to upgrade ruby. Details When reading text nodes from an XML document, the REXML parser can be coerced in to allocating extremely large string objects which can consume all of the memory on a machine, causing a denial of service. Impacted code will look something like this: document = REXML::Document.new some_xml_doc document.root.text When the `text` method is called, entities will be expanded. An attacker can send a relatively small XML document that, when the entities are resolved, will consume extreme amounts of memory on the target system. Note that this attack is similar to, but different from the Billion Laughs attack. This is also related to CVE-2013-1664 of Python. All users running an affected release should either upgrade or use one of the work arounds immediately. ===== Please use CVE-2013-1821 for this issue. I apologize in advance if a CVE was requested through other channels but we need a CVE for this ASAP. Also for future reference you can get CVEs via http://people.redhat.com/kseifrie/CVE-OpenSource-Request-HOWTO.html

References:

http://people.redhat.com/kseifrie/CVE-OpenSource-Request-HOWTO.html
http://www.ruby-lang.org/en/news/2013/02/22/rexml-dos-2013-02-22/
http://seclists.org/oss-sec/2013/q1/596


Vote for this issue:
50%
50%


 

Thanks for you vote!


 

Thanks for you comment!
Your message is in quarantine 48 hours.

Comment it here.


(*) - required fields.  
{{ x.nick }} | Date: {{ x.ux * 1000 | date:'yyyy-MM-dd' }} {{ x.ux * 1000 | date:'HH:mm' }} CET+1
{{ x.comment }}

Copyright 2024, cxsecurity.com

 

Back to Top