Bug 1331461 – CVE-2016-1547 ntp: crypto-NAK preemptable association denial of service

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Bug 1331461 - (CVE-2016-1547) CVE-2016-1547 ntp: crypto-NAK preemptable association denial of service

Summary:	CVE-2016-1547 ntp: crypto-NAK preemptable association denial of service

Status:	CLOSED ERRATA

Aliases:	CVE-2016-1547

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
Docs Contact:

URL:
Whiteboard:	impact=moderate,public=20160426,repor...
Keywords:	Security

Depends On:	1332478 1332479 1332480 1332481 1356967
Blocks:	1331437
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Reported:	2016-04-28 10:50 EDT by Martin Prpič
Modified:	2016-08-03 03:43 EDT (History)
CC List:	6 users (show)

See Also:
Fixed In Version:	ntp 4.2.8p7
Doc Type:	Bug Fix
Doc Text:	A denial of service flaw was found in the way NTP handled preemptable client associations. A remote attacker could send several crypto NAK packets to a victim client, each with a spoofed source address of an existing associated peer, preventing that client from synchronizing its time.
Story Points:	---
Clone Of:
Environment:
Last Closed:	2016-05-31 04:23:15 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Knowledge Base (Solution)	2300641	None	None	None	2016-05-05 21:28 EDT
Red Hat Product Errata	RHSA-2016:1141	normal	SHIPPED_LIVE	Moderate: ntp security update	2016-05-31 08:11:54 EDT
Red Hat Product Errata	RHSA-2016:1552	normal	SHIPPED_LIVE	Moderate: ntp security update	2016-08-03 07:43:21 EDT

Groups: None (edit)

Description Martin Prpič 2016-04-28 10:50:51 EDT

The following flaw was found in NTP:

An off-path attacker can cause a preemptable client association to be demobilized by sending a crypto NAK packet to a victim client with a spoofed source address of an existing associated peer. This is true even if authentication is enabled.

Furthermore, if the attacker keeps sending crypto NAK packets, for example every one second, the victim never has a chance to reestablish the association and synchronize time with the legitimate server.

Upstream bugs:

http://support.ntp.org/bin/view/Main/NtpBug3007

External References:

http://support.ntp.org/bin/view/Main/SecurityNotice#April_2016_NTP_4_2_8p7_Security
http://www.talosintel.com/reports/TALOS-2016-0081/

Comment 2 Miroslav Lichvar 2016-05-10 09:51:11 EDT

In Fedora this bug was fixed in ntp-4.2.6p5-36.fc22 and ntp-4.2.6p5-36.fc23 as a part of the fix for CVE-2015-7979.

Comment 3 errata-xmlrpc 2016-05-31 04:12:44 EDT

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7
  Red Hat Enterprise Linux 6

Via RHSA-2016:1141 https://access.redhat.com/errata/RHSA-2016:1141

Comment 5 errata-xmlrpc 2016-08-03 03:43:39 EDT

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6.7 Extended Update Support

Via RHSA-2016:1552 https://rhn.redhat.com/errata/RHSA-2016-1552.html

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