Hackin9

We have received a report theNational Finance Center site www.nfc.usda.gov is currently returning a 500: Server Error (thanks Melissa) and the U.S. Department of Agriculture www.usda.gov is returning an IBM HTTP WebSphere software page. We are currently investigating to get additional information.

Update 1: www.usda.gov is now back up at 02:30 GMT

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Guy Bruneau IPSS Inc. gbruneau at isc dot sans dot edu

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.
 

While people generally know where their real NTP servers are, all to often they dont know that theyve got a raft of accidental NTP servers - boxes that have NTP enabled without the system maintainers knowing about it. Common servers on the network like routers or switches (often when these are NTP clients, they are also NTP servers), PBXs and VOIP gateways, mail servers, certificate authorities and so on.

In these days of auto-updates, you would think that most NTP servers would be patched against the vulnerabilities found by the Google team and described in story written up by Johannes earlier this evening.

However, it only took until the second host checked to find a very out of date server. Unfortunately, its the main NTP server of a large Canadian ISP (Oops). What I also found along the way was that many servers only report 4 as a version, and that from the -sV switch, not from ntp-info. So depending on your internal servers and how they are configured, it may be time for us to start using authenticated scans using tools like Nessus to get service versions for our NTP servers. Hopefully that">C:\">Nmap scan report for ntp.someisp.ca (x.x.x.x)
Host is up (0.0045s latency).
rDNS record for x.x.x.x: khronos.tor.someisp.ca
PORT STATE SERVICE VERSION
123/udp open ntp NTP v4
| ntp-info:
| receive time stamp: 2014-12-20T02:47:52
|">version: ntpd [email protected] Thu Feb 13 12:17:19 EST 2003 (1)
| processor: i686
| system: Linux2.4.20-8smp
| leap: 0
| stratum: 3
| precision: -17
| rootdelay: 11.079
| rootdispersion: 33.570
| peer: 32471
| refid: x.x.x.x
| reftime: 0xd83f5fad.b46b9c30
| poll: 10
| clock: 0xd83f61d5.3a71ef30
| state: 4
| offset: -0.329
| frequency: 46.365
| jitter: 3.468
|_">Service detection performed. Please report any incorrect results at http://nmap.
org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 180.08 seconds

This server on the other hand, doesnt report the version in the ntp-info output. -sV reports version 4, but that">C:\ ">Nmap scan report for time.someotherserver.com (y.y.y.y)
Host is up (0.010s latency).
PORT STATE SERVICE VERSION
123/udp open ntp NTP v4
| ntp-info:
|_">Service detection performed. Please report any incorrect results at http://nmap.
org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 143.24 seconds

But really, after this year of vulnerabilties that weve seen in basic system services, its about time that folks took the SANS Top 20 to heart - the SANS Critical Controls that you really should be looking at if its your goal to secure your network - https://www.sans.org/critical-security-controls . The top 5 in the list sum up your first line of defense against stuff like this. Know whats on your network, know whats running on that, have a formal program of patches and updates, and scan regularly for new hosts, new services and new vulnerabilities. If its your thought that a single scan for this one vulnerability is the most important thing on your plate (or scanning for heartbleed or shellshock was earlier this year), then you have already lost - it">Quick Addendum/Update (Johannes):

CentOS and other Linux distros did release updates. However, the version string may not change. Check the Build Date. For example, on CentOS6:
Before patch:ntpd [email protected] Sat Nov 23 18:21:48 UTC 2013 (1)
After patch:">">" type="cosymantecnisbfw">

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