cis-bind-v100-6-1

name	cis-bind-v100-6-1
description	Hide BIND Version String (Automated)
category	cis-bind
version	1.0
author	cyberstrike-official
tags	["cis","bind","dns","isc-bind","bind9","information-leakage"]
cis_id	6.1
cis_benchmark	CIS ISC BIND DNS Server 9.11 Benchmark v1.0.0
tech_stack	["bind","isc-bind","dns","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS 6.1 — Hide BIND Version String

Profile Applicability

• Authoritative Name Server Level 1
• Caching Only Name Server Level 1

Description

BIND includes a built-in zone, version.bind which may be queried to get the version of the name server. The version may be set to a value of none, to disable reporting of the version information.

Rationale

Making detailed BIND version information easy to obtain remotely helps attackers automate and target their attacks. The information is not necessary for the health of the server, and should not be disclosed.

Impact

Not specified in the PDF.

Audit Procedure

Use the dig command shown below to query the chaos class TXT record on version.bind. If there is no output from the command, or if a value of No Info or None is returned then the configuration is compliant.

$ dig @ns1.cisecurity.org version.bind chaos txt | grep '^version.bind.' | grep TXT
version.bind. 0 CH TXT "No Info"

$ dig @ns2.cisecurity.org version.bind chaos txt | grep '^version.bind.' | grep TXT
$

Remediation

Add or modify the version option to have a value of none in the BIND global options, as shown below.

options {
version "none";
. . .
}

Default Value

Default value returns the current BIND detailed version.

References

Not specified in the PDF.

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v6	9 Limitation and Control of Network Ports, Protocols, and Services	Y	Y	Y
v7	13.2 Remove Sensitive Data or Systems Not Regularly Accessed by Organization	N	Y	Y

MITRE ATT&CK Mappings

Tactic	Technique
Reconnaissance	T1592.002 - Gather Victim Host Information: Software
Discovery	T1082 - System Information Discovery

Profile

• Level 1 - Authoritative Name Server
• Level 1 - Caching Only Name Server