Bug 1433987 (CVE-2017-6464) - CVE-2017-6464 ntp: Denial of Service via Malformed Config
Summary: CVE-2017-6464 ntp: Denial of Service via Malformed Config
Alias: CVE-2017-6464
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL: http://bugs.ntp.org/show_bug.cgi?id=3389
Depends On: 1435163 1437714 1437715 1437716 1437717 1499184
Blocks: 1434021 1498774
TreeView+ depends on / blocked
Reported: 2017-03-20 13:55 UTC by Adam Mariš
Modified: 2021-03-11 15:04 UTC (History)
17 users (show)

Fixed In Version: ntp 4.2.8p10, ntp 4.3.94
Doc Type: If docs needed, set a value
Doc Text:
A vulnerability was discovered in the NTP server's parsing of configuration directives. A remote, authenticated attacker could cause ntpd to crash by sending a crafted message.
Clone Of:
Last Closed: 2017-10-26 07:10:28 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2017:3071 0 normal SHIPPED_LIVE Moderate: ntp security update 2017-10-26 11:03:10 UTC
Red Hat Product Errata RHSA-2018:0855 0 None None None 2018-04-10 08:26:21 UTC

Description Adam Mariš 2017-03-20 13:55:36 UTC
A vulnerability found in the NTP server makes it possible for an authenticated remote user to crash ntpd via a malformed mode configuration directive.


Properly monitor your ntpd instances, and auto-restart ntpd (without -g) if it stops running.

Comment 1 Adam Mariš 2017-03-20 13:55:42 UTC

Name: the NTP project
Upstream: Cure53

Comment 5 Adam Mariš 2017-03-23 10:08:10 UTC
Created ntp tracking bugs for this issue:

Affects: fedora-all [bug 1435163]

Comment 7 Doran Moppert 2017-03-30 05:53:44 UTC
In ntp-4.2.6p5 and ntp-4.2.4p8, the ttl value is an unsigned char (rather than uint32), limiting the OOB read to a (256-8)-byte region. Testing on x86_64 fails to cause a crash.

Different compiler or linker options, or different hardware, could still result in a crash being possible through this vector.

Comment 10 nupur priya 2017-04-27 07:38:40 UTC
Is RHEL-7 vulnerable to this?

Comment 18 errata-xmlrpc 2017-10-26 07:03:44 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6

Via RHSA-2017:3071 https://access.redhat.com/errata/RHSA-2017:3071

Comment 19 errata-xmlrpc 2018-04-10 08:26:11 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2018:0855 https://access.redhat.com/errata/RHSA-2018:0855

Note You need to log in before you can comment on or make changes to this bug.