DNS Cache Information leak

Posted on 2011-10-19
Last Modified: 2012-05-12
4.      DNS Service Cache Information Leak

Description: This host is running a DNS service. This service contains a
remote cache information leak. It is possible for a remote attacker
to leverage this flaw to determine what domains have been
accessed recently and gather information about the traffic patterns
on the network.

Solution: This issue can be resolved by restricting access to the DNS cache
server to internal users only.

How do i do this?
Question by:Tsz109
    LVL 76

    Expert Comment

    Are you allowing external access to your DNS service?
    If this DNS service is only used internally, there is nothing you need to do.
    If you can remotely access and query this dns server, please provide information on what it is being used for. i.e. do you use your own DNS server for a public domain?

    The solution is clearly outlined in the item you posted.

    Author Comment

    We have a setup where we login to a secure citrix environment but this is only for people with accounts and it is a secure domain down at our datacenter. We do use our own dns server for a public domain.

    The thing i am asking is how do i go about restricting access to dns cache server to internal users only.
    LVL 76

    Accepted Solution

    Is Your DNS server accessible from outside? i.e. do you have a firewall rule that directs traffic from your public IP port 53 to your DNS server's internal IP port 53?
    What did you use and how did you run the test that gave you the above errorr?

    Vulnerability scanning should always be done from outside the network to deal with external attack vectors.
    Testing the same internally only reveals the running services and then you have to determine whether those services should be running/needed?

    If you are running a Vulnerability scan while behind the firewall (internally), you get information that should someone infiltrate your organization i.e. you have an unsecured network connection through which the systems can be compromised.

    Author Comment

    this was an external vulnerability assessment that was done for my company before i got here and now they want me to fix it. Firewall, i have no control over because it is managed by our parent company.

    Thanks for your help

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