VMware vCenter Server Appliance 5.5.0 Has An Insecure NTP Server

Update: I have updated this article to reflect some new information provided by VMware. I have also published new notes and discussion as a separate blog post. On January 10, 2014 a vulnerability in ntpd, the Network Time Protocol daemon, was made public (US CERT VU#348126): UDP protocols such as NTP can be abused to amplify denial-of-service attack traffic. Servers running the network time protocol (NTP) based on implementations of ntpd prior to version 4.2.7p26 that use the default unrestricted query configuration are susceptible to a reflected denial-of-service (DRDoS) attack. Other proprietary NTP implementations may also be affected. I have encountered several vCenter Server Appliances, version 5.5.0 build 1476327 and older, that were exposed to the general Internet, and have …

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VMware vCenter Server Appliance & NTP

If you’re trying to configure NTP on the VMware vCenter Server Appliance (vCSA) 5.1 builds 799730, 880472, or 947940 according to the official documentation you might be seeing what I’m seeing: vcenter:~ # yast2 ntp-client add server=0.us.pool.ntp.org Error: Cannot update the dynamic configuration policy. vcenter:~ # yast2 ntp-client enable Error: Cannot update the dynamic configuration policy. This appears to be a SuSE bug. Seems serious but it isn’t, the commands actually do complete correctly. If you want to check the work just use the command: cat /etc/ntp.conf to check for lines starting with “server” near the bottom. /sbin/chkconfig ntp on will enable the service at boot, and /etc/rc.d/ntp start will start it immediately if it isn’t started. /usr/sbin/ntpq -p will …

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