Bug 1331465 (CVE-2016-1551)

Summary: CVE-2016-1551 ntp: ntpd reference clock impersonation
Product: [Other] Security Response Reporter: Martin Prpič <mprpic>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: mlichvar, sardella
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: ntp 4.2.8p7 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2016-05-02 11:55:55 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On:    
Bug Blocks: 1331437    

Description Martin Prpič 2016-04-28 14:52:27 UTC 
The following flaw was found in ntpd:

While the majority OSes implement martian packet filtering in their network stack, at least regarding 127.0.0.0/8, a rare few will allow packets claiming to be from 127.0.0.0/8 that arrive over physical network. On these OSes, if ntpd is configured to use a reference clock an attacker can inject packets over the network that look like they are coming from that reference clock.

Upstream bugs:

http://support.ntp.org/bin/view/Main/NtpBug3020

External References:

http://support.ntp.org/bin/view/Main/SecurityNotice#April_2016_NTP_4_2_8p7_Security
http://www.talosintel.com/reports/TALOS-2016-0132/
Comment 1 Martin Prpič 2016-05-02 11:55:55 UTC 
Statement:

This issue did not affect the versions of ntp as shipped with Red Hat Enterprise Linux 5, 6, and 7 as the Linux kernel drops packets from 127.0.0.0/8, mitigating this issue.