Bug 1331467 (CVE-2016-2517)

Summary: CVE-2016-2517 ntp: certain remote configuration values not properly validated
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: jaeshin, mdshaikh, mlichvar, sardella, slawomir
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 12:51:14 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: 1332160    
Bug Blocks: 1331437    

Description Martin Prpič 2016-04-28 14:53:12 UTC 
The following flaw was found in ntpd:

If ntpd was expressly configured to allow for remote configuration, a malicious user who knows the controlkey for ntpq or the requestkey for ntpdc (if mode7 is expressly enabled) can create a session with ntpd and then send a crafted packet to ntpd that will change the value of the trustedkey, controlkey, or requestkey to a value that will prevent any subsequent authentication with ntpd until ntpd is restarted. 

Upstream bugs:

http://support.ntp.org/bin/view/Main/NtpBug3010

External References:

http://support.ntp.org/bin/view/Main/SecurityNotice#April_2016_NTP_4_2_8p7_Security
Comment 1 Martin Prpič 2016-05-02 11:37:53 UTC 
Created ntp tracking bugs for this issue:

Affects: fedora-all [bug 1332160]
Comment 2 Martin Prpič 2016-05-02 12:51:14 UTC 
Statement:

Red Hat Product Security does not consider this to be a security issue. An authenticated user could use various other means to disable access to an NTP server (for example, using the 'restrict' command). To mitigate this issue, disable remote configuration of NTP, or restrict this ability to trusted users.