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AVG Updates on DMZ

Posted on 2013-01-01
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Last Modified: 2013-11-22
Screen shot of identified network objects inside updates groupThe environment:  Retail locations (PCI-DSS applicable) Point of Sale registers running Windows XP OS segmented onto a DMZ.  Each register runs a Kaseya agent with End Point Security  (AVG antivirus).  Each location has a SonicWall TZ 215 appliance.

I am having issues updating the AVG installs on the registers.  My DMZ rules allow HTTP access to predestinated websites only (2 commerce processing sites and AVG).  I quickly discovered the initial AVG update site was inadequate, so I created an AVGUpdateSites network address object and then grouped various update sites (other network address objects) that the log files were showing AVG was trying to access.

I'm up to 15 different update sites now and have some fourth level domain transport companies (e.g. akamaitechnogies.com, nlayer.net, etc...) that seem to change daily.  I need to allow access for all of these AVG update sites and block everything else.

I'm looking for ideas of how to better skin this cat.  Still haven't spoken to anyone at AVG that even knew they were using these dynamic sites.  Attached is a pic of the sites I've currently identified.  It shows a few different attempts at the 3rd and 4th level domain attempts - none work.
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Question by:HoneyFarms
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by:carlmd
ID: 38736137
Take a look at these two links. They pertain to the free version, but may help.

http://free.avg.com/faq.num-2416#faq_2416

http://free.avg.com/faq.num-2419#faq_2419
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by:HoneyFarms
ID: 38736308
Thanks, but no.  I guess I'm really looking for how I can allow for akamai's and nlayer's dyamic third and fourth level domain name changes.  SonicWall doesn't support wildcards at that level - won't resolve.
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by:carlmd
ID: 38736333
This link contains a list of what is supposed to be "all" the sites you need to permit a connection to. Have you permitted all of these?

http://free.avg.com/us-en/faq.num-2446#faq_2446
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by:btan
ID: 38736408
Just to add on, looks like different AVG version (below are the commercial versions) may have different list to be put into exception for Sonicwall to allow

2013 - http://www.avg.com/ww-en/faq.num-5229
2011 - http://www.avg.com/ww-en/faq.num-3487
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by:Aaron Tomosky
ID: 38736961
For the Akamai you have do do each level with a star.
*.akamai.com
*.something.akamai.com
*.5.something.akamai.com

The * will do anything except a subdomain.
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Author Comment

by:HoneyFarms
ID: 38745303
Thanks for the responses, but the objects have to be IP host addresses, IP range, IP network or a resolvable FQDN, which rules out the wildcards.  When you ping the URL's listed on the referenced pages, you end up with a list of IP addresses that represent less than 30% of the total addresses and ranges I've discovered through firewall logs today.  Everything I force an update to the AVG agents I get new sites being blocked.  I account fo rthose sites, update again, and get new blocks.  There has to be a inclusive list somewhere.

Any other ideas?  Thanks!
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by:btan
ID: 38746304
See this http://www.experts-exchange.com/Virus_and_Spyware/Anti-Virus/Q_23957383.html

just curious as I saw some sonicwall config guide on address object accepting wildcard, maybe I am missing out something

http://help.sonicwall.com/help/sw/eng/6800/25/8/1/Network_netObjView.html

...If you selected FQDN , enter the domain name for the individual site or range of sites (with a wildcard) in the FQDN field.

....FQDN Address Objects support wildcard entries, such as “*.somedomainname.com”, by first resolving the base domain name to all its defined host IP addresses, and then by constantly actively gleaning DNS responses as they pass through the firewall.
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by:HoneyFarms
ID: 38746750
Yeah, I thought the same thing.  I opened a ticket with SonicWall and they confirmed that wildcards used in network address objectives won't resolve.  For poops and giggles I added it back to a store and forced an update.  Attached is a pic from the log showing it won't resolve.  Wish I could.  I already added the reefernced sites to the matrix and still got the same results.
fqdn.jpg
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by:btan
ID: 38746875
Looks like if the firewall cannot perform the DNS lookup the ip cannot be resolved. Suspecting that browsing to that dynamic DNS site is not possible at all as well...most AV uses such so that update server is always available. Minimally the nslookup or dig should return the ip address though it changes subsequently...try robtex or domain dossier on the host to see the possible ip address.

Sigh - http://serverfault.com/questions/376794/i-need-to-create-a-special-rule-on-my-firewall-with-all-the-ip-addresses-from-fa

I did saw some innovative ways but tough
http://michigantelephone.wordpress.com/2011/06/28/using-dyndns-to-solve-the-problem-of-keeping-a-firewall-open-to-remote-users-at-changeable-ip-addresses/
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by:Aaron Tomosky
ID: 38746960
I personally use * in fqdn fields and. It works just fine. However I do have DNA setup so it can resolve them.
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btan earned 500 total points
ID: 38748147
if you will to see the sonicwall link in my post, it did state SonicOS Enhanced 3.5 stating below [1] and it also added more [2]. You may want to ask them on "Sanctioned DNS server" - see section "Enforcing the use of sanctioned servers on the network". Definition [3]

[1]"...FQDN – Fully Qualified Domain Names, such as ‘www.reallybadWebsite.com’, will be resolved to their IP address (or IP addresses) using the DNS server configured on the SonicWALL. Wildcard entries are supported through the gleaning of responses to queries sent to the sanctioned DNS servers...."

[2]Since most DNS servers do not allow zone transfers, it is typically not possibly to automatically enumerate all the hosts in a domain. Instead, the SonicWALL will look for DNS responses coming from sanctioned DNS servers as they traverse the firewall. So if a host behind the firewall queries an external DNS server which is also a configured/defined DNS server on the SonicWALL, the SonicWALL will parse the response to see if it matches the domain of any wildcard FQDN AOs.

[3] Sanctioned DNS servers are those DNS servers configured for use by the SonicWALL firewall. The reason that responses from only sanctioned DNS servers are used in the wildcard learning process is to protect against the possibility of FQDN AO poisoning through the use of unsanctioned DNS servers with deliberately incorrect host entries.


Overall, minimally FW to allow such DNS resolving to see the traces to Akamai DNS server @ http://en.wikipedia.org/wiki/Akamai_Technologies#Akamai.27s_DNS_servers

That is why, I am puzzled why the sonicwall support say "...confirmed that wildcards used in network address objectives won't resolve..." - may want to drill further assuming the above is valid


Side note
 - Sonicwall has the section on "Blocking All Protocol Access to a Domain using FQDN DAOs"
 - Some past conjectures of akamai related working
@ http://research.microsoft.com/en-us/um/people/ratul/akamai.html
 - Akamai NetworkSession Interface (installed in client machine)
@ http://www.akamai.com/html/solutions/client_faq.html
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