The DNS Name Server software must be configured to refuse queries for its version information.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-58737	WDNS-SI-000003	SV-83227r1_rule		Medium

Description
Each newer version of the name server software, especially the BIND software, generally is devoid of vulnerabilities found in earlier versions because it has design changes incorporated to take care of those vulnerabilities. Of course, these vulnerabilities have been exploited (i.e., some form of attack was launched), and sufficient information has been generated with respect to the nature of those exploits. Thus, it makes good business sense to run the latest version of name server software because theoretically it is the safest version. In some installations, it may not be possible to switch over to the latest version of name server software immediately. If the version of the name server software is revealed in queries, this information may be used by attackers who are looking for a specific version of the software which has a discovered weakness. To prevent information about which version of name server software is running on a system, name servers should be configured to refuse queries for its version information.

Description

Each newer version of the name server software, especially the BIND software, generally is devoid of vulnerabilities found in earlier versions because it has design changes incorporated to take care of those vulnerabilities. Of course, these vulnerabilities have been exploited (i.e., some form of attack was launched), and sufficient information has been generated with respect to the nature of those exploits. Thus, it makes good business sense to run the latest version of name server software because theoretically it is the safest version. In some installations, it may not be possible to switch over to the latest version of name server software immediately. If the version of the name server software is revealed in queries, this information may be used by attackers who are looking for a specific version of the software which has a discovered weakness. To prevent information about which version of name server software is running on a system, name servers should be configured to refuse queries for its version information.

STIG	Date
Microsoft Windows 2008 Server Domain Name System Security Technical Implementation Guide	2019-01-04

Details

Check Text ( C-59609r2_chk )
The "EnableVersionQuery" property controls what version information the DNS server will respond with when a DNS query with class set to “CHAOS” and type set to “TXT” is received. Log on to the DNS server using the Domain Admin or Enterprise Admin account. Open a command window and execute the command: nslookup Note: Confirm the Default Server is the DNS Server on which the command is being run. At the nslookup prompt, type: set type=TXT set class=CHAOS version.bind If the response returns something similar to text = "Microsoft DNS 6.1.7601 (1DB14556)", this is a finding.

Check Text ( C-59609r2_chk )

The "EnableVersionQuery" property controls what version information the DNS server will respond with when a DNS query with class set to “CHAOS” and type set to “TXT” is received.

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

Open a command window and execute the command:

nslookup
Note: Confirm the Default Server is the DNS Server on which the command is being run.

At the nslookup prompt, type:

set type=TXT
set class=CHAOS
version.bind

If the response returns something similar to text = "Microsoft DNS 6.1.7601 (1DB14556)", this is a finding.

Fix Text (F-64121r2_fix)
To disable the version being returned in queries, execute the following command: dnscmd /config /EnableVersionQuery 0