Bug 1176032 (CVE-2014-9293) - CVE-2014-9293 ntp: automatic generation of weak default key in config_auth()
Summary: CVE-2014-9293 ntp: automatic generation of weak default key in config_auth()
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2014-9293
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1176067 1176068 1176069 1176070 1176100 1176191 1176680 1182166
Blocks: 1176041
TreeView+ depends on / blocked
 
Reported: 2014-12-19 08:50 UTC by Huzaifa S. Sidhpurwala
Modified: 2019-09-29 13:25 UTC (History)
14 users (show)

Fixed In Version: ntp 4.2.8
Doc Type: Bug Fix
Doc Text:
It was found that ntpd automatically generated weak keys for its internal use if no ntpdc request authentication key was specified in the ntp.conf configuration file. A remote attacker able to match the configured IP restrictions could guess the generated key, and possibly use it to send ntpdc query or configuration requests.
Clone Of:
Environment:
Last Closed: 2014-12-20 02:47:42 UTC


Attachments (Terms of Use)


Links
System ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2014:2024 normal SHIPPED_LIVE Important: ntp security update 2014-12-20 07:40:29 UTC
Red Hat Product Errata RHSA-2014:2025 normal SHIPPED_LIVE Important: ntp security update 2014-12-20 05:43:37 UTC
Red Hat Product Errata RHSA-2015:0104 normal SHIPPED_LIVE Important: ntp security update 2015-01-28 23:52:05 UTC

Description Huzaifa S. Sidhpurwala 2014-12-19 08:50:56 UTC
As per upstream NTP security advisory:

If no 'auth' key is set in the configuration file, ntpd  would generate a random key on the fly.  There were two problems with this: 1) the generated key was 31 bits in size, and 2) it used the (now weak) ntp_random() function, which was seeded with a 32-bit value and could only provide 32 bits of entropy.  This was sufficient back in the late 1990s when the code was written.  Not today.

Mitigation: Upgrade to 4.2.7p11 or later.

This vulnerability was noticed in ntp-4.2.6 by Neel Mehta of the Google Security Team.

Comment 1 Tomas Hoger 2014-12-19 09:06:51 UTC
Upstream mentions the issue was fixed in 4.2.7p11.  The following commit from between 4.2.7p10 and 4.2.7p11 seems to remove automatic auth key generation among other changes.  Commit message does not mention removal of the code at all:

http://bk1.ntp.org/ntp-dev/ntpd/ntp_config.c?PAGE=diffs&REV=4b6089c5KXhXqZqocF0DMXnQQsjOuw

Upstream change to the NEWS file with details quoted in comment 0:

http://bk1.ntp.org/ntp-dev/?PAGE=patch&REV=5493dc3dofY6drKJde9W-5O1M3s4eg

Comment 8 Tomas Hoger 2014-12-19 13:45:17 UTC
Upstream bug:
http://bugs.ntp.org/show_bug.cgi?id=2665

Comment 11 Tomas Hoger 2014-12-19 16:21:30 UTC
Created ntp tracking bugs for this issue:

Affects: fedora-all [bug 1176191]

Comment 12 errata-xmlrpc 2014-12-20 00:44:21 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 5

Via RHSA-2014:2025 https://rhn.redhat.com/errata/RHSA-2014-2025.html

Comment 13 errata-xmlrpc 2014-12-20 02:40:35 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6
  Red Hat Enterprise Linux 7

Via RHSA-2014:2024 https://rhn.redhat.com/errata/RHSA-2014-2024.html

Comment 14 Fedora Update System 2014-12-22 02:37:28 UTC
ntp-4.2.6p5-19.fc20 has been pushed to the Fedora 20 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 18 Fedora Update System 2014-12-23 18:28:34 UTC
ntp-4.2.6p5-25.fc21 has been pushed to the Fedora 21 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 20 Fedora Update System 2014-12-31 19:00:28 UTC
ntp-4.2.6p5-13.fc19 has been pushed to the Fedora 19 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 22 Tomas Hoger 2015-01-07 12:07:15 UTC
Blog post from the original reporter, which mentions how this issue can help with exploitation of other issue (CVE-2014-9295, bug 1176037):

http://googleprojectzero.blogspot.com/2015/01/finding-and-exploiting-ntpd.html

Comment 24 Florian Weimer 2015-01-07 16:28:50 UTC
Mitigation:

Issue these commands to explicitly generate a strong key and add it to the
ntpd configuration:

    echo trustedkey 65535 >> /etc/ntp.conf
    printf "65535\tM\t%s\n" $(tr -cd a-zA-Z0-9 < /dev/urandom | head -c 16) >> /etc/ntp/keys

The generated key has about 95 bits of entropy.

Comment 26 errata-xmlrpc 2015-01-28 18:52:18 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6.5 EUS - Server and Compute Node Only

Via RHSA-2015:0104 https://rhn.redhat.com/errata/RHSA-2015-0104.html


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