Bug 963186 - python-backports-ssl_match_hostname: Denial of service when matching certificate with many '*' wildcard characters
python-backports-ssl_match_hostname: Denial of service when matching certific...
Status: CLOSED DUPLICATE of bug 963260
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
unspecified
All Linux
low Severity low
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Assigned To: Red Hat Product Security
impact=low,public=20130515,reported=2...
: Security
Depends On:
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Reported: 2013-05-15 07:02 EDT by Jan Lieskovsky
Modified: 2013-05-15 10:50 EDT (History)
2 users (show)

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Doc Type: Bug Fix
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Last Closed: 2013-05-15 10:50:18 EDT
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Description Jan Lieskovsky 2013-05-15 07:02:05 EDT
A denial of service flaw was found in the way python-backports-ssl_match_hostname, an implementation that brings the ssl.match_hostname() function from Python 3.2 to users of earlier versions of Python, performed matching of the certificate's name in the case it contained many '*' wildcard characters. A remote attacker, able to obtain valid certificate with its name containing a lot of '*' wildcard characters, could use this flaw to cause denial of service (excessive CPU time consumption) by issuing request to validate that certificate for / in an application using the python-backports-ssl_match_hostname functionality.

Upstream bug report:
[1] http://bugs.python.org/issue17980

Acknowledgements:

This issue was discovered by Florian Weimer of Red Hat Product Security Team.
Comment 1 Jan Lieskovsky 2013-05-15 07:04:40 EDT
This issue affects the versions of the python-backports-ssl_match_hostname package as shipped with Fedora release of 17, 18, and Fedora EPEL-6. Please schedule an update (once there is final upstream patch available).
Comment 2 Jan Lieskovsky 2013-05-15 07:07:04 EDT
Created python-backports-ssl_match_hostname tracking bugs for this issue

Affects: fedora-all [bug 963187]
Affects: epel-6 [bug 963188]
Comment 3 Jan Lieskovsky 2013-05-15 07:37:20 EDT
CVE request:
  http://www.openwall.com/lists/oss-security/2013/05/15/6

and Python 3.2 case follow-up:
  http://www.openwall.com/lists/oss-security/2013/05/15/7
(will file independent Python 3.2 bug shortly - after the lunch)
Comment 4 Jan Lieskovsky 2013-05-15 10:50:18 EDT

*** This bug has been marked as a duplicate of bug 963260 ***

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