V-215647

Discussion

Limiting the number of concurrent sessions reduces the risk of Denial of Service (DoS) on any system. A DNS server's function requires it to be able to handle multiple sessions at a time so limiting concurrent sessions could potentially cause an impact to availability. Primary name servers need to be configured to limit the actual hosts from which they will accept dynamic updates and from which they will accept zone transfer requests, and all name servers should be configured to limit the hosts from/to which they receive/send zone transfers. Restricting sessions to known hosts will mitigate the DoS vulnerability.

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Log on to the DNS server using the Domain Admin or Enterprise Admin account or Local Administrator account.

Press Windows Key + R, execute dnsmgmt.msc.

On the opened DNS Manager snap-in from the left pane, expand the server name and then expand Forward Lookup Zones.

From the expanded list, click to select the zone.

Once selected, right-click the name of the zone.

From the displayed context menu, click the “Properties” option.

On the opened domain's properties box, click the “General” tab.

Verify the Type: is Active Directory-Integrated.

Verify the Dynamic updates has "Secure only" selected.

If the zone is Active Directory-Integrated and the Dynamic updates are not configured for "Secure only", this is a finding.