Bug 1397347 (CVE-2016-7433)

Summary:	CVE-2016-7433 ntp: Broken initial sync calculations regression
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	apmukher, bphinz, keyur.three0, mlichvar, sardella, slawomir, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in the way ntpd calculated the root delay. A remote attacker could send a specially-crafted spoofed packet to cause denial of service or in some special cases even crash.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-02-06 06:50:38 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1397351, 1411642, 1411643, 1411644, 1411645
Bug Blocks:	1397349

Description Adam Mariš 2016-11-22 11:00:52 UTC

Bug 2085 described a condition where the root delay was included twice, causing the jitter value to be higher than expected. Due to a misinterpretation of a small-print variable in The Book, the fix for this problem was incorrect, resulting in a root distance that did not include the peer dispersion. The calculations and formulae have been reviewed and reconciled, and the code has been updated accordingly.

External References:

http://support.ntp.org/bin/view/Main/NtpBug3067

Comment 1 Adam Mariš 2016-11-22 11:09:40 UTC

Created ntp tracking bugs for this issue:

Affects: fedora-all [bug 1397351]

Comment 2 Huzaifa S. Sidhpurwala 2017-01-04 08:21:54 UTC

Analysis:

When an offpath attacker can spoof the first ntp reply, ntpd will jump and when it gets a real response, it will exit.

Comment 4 Keyur Pujara 2017-01-16 11:30:34 UTC

Is an RPM released with fix for this. I haven't seen one @ http://mirror.centos.org. 

If not released, what is ETA for same?

Thanks, Keyur

Comment 5 Brian Hinz 2017-01-31 14:18:18 UTC

Wondering the same thing.  Is an errata update for el6/el7 forthcoming?  Thanks.

Comment 6 errata-xmlrpc 2017-02-06 06:17:50 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6
  Red Hat Enterprise Linux 7

Via RHSA-2017:0252 https://rhn.redhat.com/errata/RHSA-2017-0252.html