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Windows DNS attack feared

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Category: General Discussion
Forum Name: General Discussion
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URL: https://forums.webwiz.net/forum_posts.asp?TID=23130
Printed Date: 29 March 2026 at 12:03pm
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Topic: Windows DNS attack feared

Posted By: iSec
Subject: Windows DNS attack feared
Date Posted: 17 April 2007 at 10:56am

Don't forget to install the latest critical updates off the windows updates site...

More info: http://tech.monstersandcritics.com/news/article_1291855.php/Long_weekend_for_IT_professionals_due_to_DNS_vulnerability - http://tech.monstersandcritics.com/news/article_1291855.php/Long_weekend_for_IT_professionals_due_to_DNS_vulnerability

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"When it gets dark enough, you can see the stars"
-Charles A. Beard

Replies:

Posted By: WebWiz-Bruce
Date Posted: 17 April 2007 at 2:50pm

Microsoft haven't got a patch for it yet just instructions on how to lock down and secure your DNS server, which to be honest any good system admin would have or should have done already.

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Posted By: iSec
Date Posted: 18 April 2007 at 9:04am

Right... everyone should have their firewalls on... I'll share the following info that was recently sent to me from my hosting provider:

Dear Customer:

If you are not hosting a Dedicated Server which operates on Microsoft Windows Server Operating System, you may ignore this message.

It has been brought to our attention that Microsoft is investigating new public reports of attack exploiting a vulnerability in the Domain Name System (DNS) Server Service in Microsoft Windows 2000 Server Service Pack 4, Windows Server 2003 Service Pack 1, and Windows Server 2003 Service Pack 2.

Please refer to Microsoft Advisory Article located at: http://www.microsoft.com/technet/security/advisory/935964.mspx - http://www.microsoft.com/technet/security/advisory/935964.mspx

Fellow researchers at myNetWatchman are stating, that recently a flaw was discovered in the Microsoft DNS (Domain Name Services) Server's RPC (Remote Procedure Call) management server. This flaw is being actively exploited in the wild NOW on a limited scale but activity is expected to increase very soon. If your server is running Microsoft DNS Service with RPC over TCP (135/tcp) enabled with unrestricted remote access (e.g. NOT firewalled), then it is VULNERABLE TO THIS EXPLOIT. Compromise of this server could lead to compromise of ALL internal DNS clients that use this server as a DNS resolver!

As we always recommend, firewalling all servers with only necessary ports open is the best practice to follow. In this case if your Windows server is vulnerable if it is not firewalled properly.

We thank MyNetWatchman for proactive distribution of this information and Dan Kaminsky of DoxPara Research for this information.

If you suspect this server may already be compromised, feel free to run the myNetWatchman forensic scanner (SecCheck): http://mynetwatchman.com/tools/sc - http://mynetwatchman.com/tools/sc

If you are a Premier Managed Server Customer, the server management staff has already taken steps as recommended by Microsoft.

INFORMATION PROVIDED IN THIS EMAIL IS OFFERED TO YOU AS A CUSTOMER COURTESY. We do NOT GUARANTEE ACCURACY OF THIS INFORMATION. WE DO NOT HAVE FURTHER INFORMATION ON THIS MATTER AND THUS WE ASK OUR CUSTOMERS NOT TO OPEN SUPPORT TICKETS REGARDING THIS. OUR SYSTEM ENGINEERS WILL NOT BE ABLE TO ASSIST YOU WITH TASKS AND OR QUESTIONS RELATING TO THIS. PLEASE REFER TO MICROSOFT WEBSITE FOR MORE INFORMATION.

Customer Service

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"When it gets dark enough, you can see the stars"
-Charles A. Beard

Posted By: WebWiz-Bruce
Date Posted: 18 April 2007 at 9:55am

Another option is run a different DNS server, for some of our DNS servers we are using Simple DNS which is much better than Microsoft DNS.

The few Microsoft DNS servers that we do use we only allow open port 53, port 135 which is used for RPC and not required for running a DNS server is not open. If you close port 135 on your firewall then you shouldn't need to worry about this threat.

If you are running a web server I would close all ports except the following (depending on which services you are running):-

80 - web server
21 - FTP
25 - SMTP
53 - DNS server
110 - Pop 3
143 - IMAP 4
220 - IMAP 3
443 - SSL pages
3306 - mySQL
1433 - SQL Server
3389 - Remote desktop

If you are not remotely connecting to any of the services above, like if you only connect to SQL server using localhost, don't open the port up for it.

You can also restrict things further for example if only yourself needs to have FTP access only allow FTP on port 21 for your own computer's IP address or IP range.

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