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The Domain Name System (DNS) serves as the internet's directory, allowing users to access websites through easy-to-remember domain names like google.com or facebook.com, instead of the numeric Internet Protocol (IP) addresses. By translating domain names into IP addresses, the DNS ensures web browsers can quickly load internet resources, simplifying how we navigate the online world.
Default port: 53
PORT STATE SERVICE REASON
53/tcp open domain Microsoft DNS 6.1.7601 (1DB15D39) (Windows Server 2008 R2 SP1)
5353/udp open zeroconf udp-response
53/udp open domain Microsoft DNS 6.1.7601 (1DB15D39) (Windows Server 2008 R2 SP1)
Different DNS Servers
DNS Root Servers: These are at the top of the DNS hierarchy, managing the top-level domains and stepping in only if lower-level servers do not respond. The Internet Corporation for Assigned Names and Numbers (ICANN) oversees their operation, with a global count of 13.
Authoritative Nameservers: These servers have the final say for queries in their designated zones, offering definitive answers. If they can't provide a response, the query is escalated to the root servers.
Non-authoritative Nameservers: Lacking ownership over DNS zones, these servers gather domain information through queries to other servers.
Caching DNS Server: This type of server memorizes previous query answers for a set time to speed up response times for future requests, with the cache duration dictated by the authoritative server.
Forwarding Server: Serving a straightforward role, forwarding servers simply relay queries to another server.
Resolver: Integrated within computers or routers, resolvers execute name resolution locally and are not considered authoritative.
Enumeration
Banner Grabbing
There aren't banners in DNS but you can gran the macgic query for version.bind. CHAOS TXT which will work on most BIND nameservers.
You can perform this query using dig:
digversion.bindCHAOSTXT@DNS
Moreover, the tool fpdns can also fingerprint the server.
It's also possible to grab the banner also with a nmap script:
--script dns-nsid
Any record
The record ANY will ask the DNS server to return all the available entries that it is willing to disclose.
diganyvictim.com@<DNS_IP>
Zone Transfer
This procedure is abbreviated Asynchronous Full Transfer Zone (AXFR).
digaxfr@<DNS_IP>#Try zone transfer without domaindigaxfr@<DNS_IP><DOMAIN>#Try zone transfer guessing the domainfierce --domain <DOMAIN> --dns-servers <DNS_IP> #Will try toperform a zone transfer against every authoritative name server and if this doesn'twork, will launch a dictionary attack
More info
digANY@<DNS_IP><DOMAIN>#Any informationdigA@<DNS_IP><DOMAIN>#Regular DNS requestdigAAAA@<DNS_IP><DOMAIN>#IPv6 DNS requestdigTXT@<DNS_IP><DOMAIN>#InformationdigMX@<DNS_IP><DOMAIN>#Emails relateddigNS@<DNS_IP><DOMAIN>#DNS that resolves that namedig-x192.168.0.2@<DNS_IP>#Reverse lookupdig-x2a00:1450:400c:c06::93@<DNS_IP>#reverse IPv6 lookup#Use [-p PORT] or -6 (to use ivp6 address of dns)
Automation
for sub in $(cat <WORDLIST>);do dig $sub.<DOMAIN> @<DNS_IP> | grep -v ';\|SOA' | sed -r '/^\s*$/d' | grep $sub | tee -a subdomains.txt;done
dnsenum--dnsserver<DNS_IP>--enum-p0-s0-osubdomains.txt-f<WORDLIST><DOMAIN>
Using nslookup
nslookup> SERVER <IP_DNS>#Select dns server> 127.0.0.1 #Reverse lookup of 127.0.0.1, maybe...><IP_MACHINE>#Reverse lookup of a machine, maybe...
#Perform enumeration actionsnmap-n--script"(default and *dns*) or fcrdns or dns-srv-enum or dns-random-txid or dns-random-srcport"<IP>
DNS - Reverse BF
dnsrecon-r127.0.0.0/24-n<IP_DNS>#DNS reverse of all of the addressesdnsrecon-r127.0.1.0/24-n<IP_DNS>#DNS reverse of all of the addressesdnsrecon-r<IP_DNS>/24-n<IP_DNS>#DNS reverse of all of the addressesdnsrecon-dactive.htb-a-n<IP_DNS>#Zone transfer
If you are able to find subdomains resolving to internal IP-addresses, you should try to perform a reverse dns BF to the NSs of the domain asking for that IP range.
#Query paypal subdomains to ns3.isc-sns.infonmap-sSU-p53--scriptdns-nsec-enum--script-argsdns-nsec-enum.domains=paypal.comns3.isc-sns.info
IPv6
Brute force using "AAAA" requests to gather IPv6 of the subdomains.
dnsdict6-s-t<domain>
Bruteforce reverse DNS in using IPv6 addresses
dnsrevenum6pri.authdns.ripe.net2001:67c:2e8::/48#Will use the dns pri.authdns.ripe.net
DNS Recursion DDoS
If DNS recursion is enabled, an attacker could spoof the origin on the UDP packet in order to make the DNS send the response to the victim server. An attacker could abuse ANY or DNSSEC record types as they use to have the bigger responses.
The way to check if a DNS supports recursion is to query a domain name and check if the flag "ra" (recursion available) is in the response:
diggoogle.comA@<IP>
Non available:
Available:
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Through the examination of a nondelivery notification (NDN) triggered by an email sent to an invalid address within a target domain, valuable internal network details are often disclosed.
The provided nondelivery report includes information such as:
The generating server was identified as server.example.com.
A failure notice for user@example.com with the error code #550 5.1.1 RESOLVER.ADR.RecipNotFound; not found was returned.
Internal IP addresses and hostnames were disclosed in the original message headers.
The original message headers were modified for anonymity and now present randomized data:Generating server: server.example.comuser@example.com#550 5.1.1 RESOLVER.ADR.RecipNotFound; not found ##Original message headers:Received: from MAILSERVER01.domain.example.com (192.168.1.1) bymailserver02.domain.example.com (192.168.2.2) with Microsoft SMTP Server (TLS)id 14.3.174.1; Mon, 25 May 2015 14:52:22 -0700Received: from filter.example.com (203.0.113.1) byMAILSERVER01.domain.example.com (192.168.1.1) with Microsoft SMTP Server (TLS)id 14.3.174.1; Mon, 25 May 2015 14:51:22 -0700X-ASG-Debug-ID: 1432576343-0614671716190e0d0001-zOQ9WJReceived: from gateway.domainhost.com (gateway.domainhost.com [198.51.100.37]) byfilter.example.com with ESMTP id xVNPkwaqGgdyH5Ag for user@example.com; Mon,25 May 2015 14:52:13 -0700 (PDT)X-Envelope-From: sender@anotherdomain.orgX-Apparent-Source-IP: 198.51.100.37
Protocol_Name: DNS #Protocol Abbreviation if there is one.
Port_Number: 53 #Comma separated if there is more than one.
Protocol_Description: Domain Name Service #Protocol Abbreviation Spelled out
Entry_1:
Name: Notes
Description: Notes for DNS
Note: |
#These are the commands I run every time I see an open DNS port
dnsrecon -r 127.0.0.0/24 -n {IP} -d {Domain_Name}
dnsrecon -r 127.0.1.0/24 -n {IP} -d {Domain_Name}
dnsrecon -r {Network}{CIDR} -n {IP} -d {Domain_Name}
dig axfr @{IP}
dig axfr {Domain_Name} @{IP}
nslookup
SERVER {IP}
127.0.0.1
{IP}
Domain_Name
exit
https://book.hacktricks.xyz/pentesting/pentesting-dns
Entry_2:
Name: Banner Grab
Description: Grab DNS Banner
Command: dig version.bind CHAOS TXT @DNS
Entry_3:
Name: Nmap Vuln Scan
Description: Scan for Vulnerabilities with Nmap
Command: nmap -n --script "(default and *dns*) or fcrdns or dns-srv-enum or dns-random-txid or dns-random-srcport" {IP}
Entry_4:
Name: Zone Transfer
Description: Three attempts at forcing a zone transfer
Command: dig axfr @{IP} && dix axfr @{IP} {Domain_Name} && fierce --dns-servers {IP} --domain {Domain_Name}
Entry_5:
Name: Active Directory
Description: Eunuerate a DC via DNS
Command: dig -t _gc._{Domain_Name} && dig -t _ldap._{Domain_Name} && dig -t _kerberos._{Domain_Name} && dig -t _kpasswd._{Domain_Name} && nmap --script dns-srv-enum --script-args "dns-srv-enum.domain={Domain_Name}"
Entry_6:
Name: consolesless mfs enumeration
Description: DNS enumeration without the need to run msfconsole
Note: sourced from https://github.com/carlospolop/legion
Command: msfconsole -q -x 'use auxiliary/scanner/dns/dns_amp; set RHOSTS {IP}; set RPORT 53; run; exit' && msfconsole -q -x 'use auxiliary/gather/enum_dns; set RHOSTS {IP}; set RPORT 53; run; exit'
Get a hacker's perspective on your web apps, network, and cloud
Find and report critical, exploitable vulnerabilities with real business impact. Use our 20+ custom tools to map the attack surface, find security issues that let you escalate privileges, and use automated exploits to collect essential evidence, turning your hard work into persuasive reports.
