Bug 1340858 – CVE-2016-4955 ntp: autokey association reset

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Bug 1340858 - (CVE-2016-4955) CVE-2016-4955 ntp: autokey association reset

Summary:	CVE-2016-4955 ntp: autokey association reset

Status:	CLOSED WONTFIX

Aliases:	CVE-2016-4955

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

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

URL:
Whiteboard:	impact=low,public=20160602,reported=2...
Keywords:	Security

Depends On:	1342128
Blocks:	1302226
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Reported:	2016-05-30 08:36 EDT by Martin Prpič
Modified:	2016-10-03 15:48 EDT (History)
CC List:	4 users (show)

See Also:
Fixed In Version:	ntp 4.2.8p8
Doc Type:	If docs needed, set a value
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Environment:
Last Closed:	2016-05-30 09:31:34 EDT
Type:	---
Regression:	---
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Documentation:	---
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oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
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Description Martin Prpič 2016-05-30 08:36:23 EDT

The following flaw was found in NTP:

An attacker can send a spoofed packet with an invalid MAC or crypto-NAK to a client/peer and reset its association if it's using autokey for authentication. If this can be done often enough, it will prevent that association from working.

Comment 1 Martin Prpič 2016-05-30 08:36:27 EDT

Acknowledgments:

Name: Miroslav Lichvar (Red Hat)

Comment 2 Martin Prpič 2016-06-02 09:39:30 EDT

Created ntp tracking bugs for this issue:

Affects: fedora-all [bug 1342128]

Comment 3 Martin Prpič 2016-06-02 09:42:40 EDT

Upstream bug:

http://support.ntp.org/bin/view/Main/NtpBug3043

External References:

http://support.ntp.org/bin/view/Main/SecurityNotice#June_2016_ntp_4_2_8p8_NTP_Securi

Comment 4 Harkanwal 2016-06-10 06:44:21 EDT

Could anyone suggest any specific reason of closing the bug without fixing it.  Secondly advisory for customers who have these vulnerabilities

Comment 5 Martin Prpič 2016-06-10 07:10:50 EDT

(In reply to Harkanwal from comment #4)
> Could anyone suggest any specific reason of closing the bug without fixing
> it.  Secondly advisory for customers who have these vulnerabilities

Hi, this issue was rated as having a Low security impact. It only affects clients that use autokey authentication, which has various known security problems by itself. Taking this into consideration, the issue is not planned to be fixed. We may revisit this issue in a future minor RHEL release.

Comment 6 Fedora Update System 2016-06-18 14:47:28 EDT

ntp-4.2.6p5-41.fc24 has been pushed to the Fedora 24 stable repository. If problems still persist, please make note of it in this bug report.

Comment 7 Fedora Update System 2016-07-02 15:26:51 EDT

ntp-4.2.6p5-41.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.

Comment 8 Fedora Update System 2016-07-02 15:32:39 EDT

ntp-4.2.6p5-41.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.

Comment 9 Martin Prpič 2016-09-27 03:44:51 EDT

Mitigation:

Disable autokey authentication. Instead, configure ntp to use symmetric key authentication, or no authentication at all (if not required). To configure ntp with symmetric key authentication, follow the steps at https://access.redhat.com/solutions/393663

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