53 - Pentesting DNS - HackTricks

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Basic Information
The Domain Name Systems (DNS) is the phonebook of the Internet. Humans access information online through domain names, like nytimes.com or espn.com. Web browsers interact through Internet Protocol (IP) addresses. DNS translates domain names to IP addresses so browsers can load Internet resources.
From here.
Default port: 53
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PORT     STATE SERVICE  REASON
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53/tcp   open  domain  Microsoft DNS 6.1.7601 (1DB15D39) (Windows Server 2008 R2 SP1)
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5353/udp open  zeroconf udp-response
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53/udp   open  domain  Microsoft DNS 6.1.7601 (1DB15D39) (Windows Server 2008 R2 SP1)
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Enumeration
Banner Grabbing
DNS does not have a "banner" to grab. The closest equivalent is a magic query for version.bind. CHAOS TXT which will work on most BIND nameservers.
You can perform this query using dig:
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dig version.bind CHAOS TXT @DNS
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If that does not work you can use fingerprinting techniques to determine the remote server's version -- the fpdns tool is one option for that, but there are others.
You can grab the banner also with a nmap script:
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--script dns-nsid
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Zone Transfer
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dig axfr @<DNS_IP> #Try zone transfer without domain
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dig axfr @<DNS_IP> <DOMAIN> #Try zone transfer guessing the domain
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fierce --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
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More info
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dig ANY @<DNS_IP> <DOMAIN>     #Any information
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dig A @<DNS_IP> <DOMAIN>       #Regular DNS request
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dig AAAA @<DNS_IP> <DOMAIN>    #IPv6 DNS request
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dig TXT @<DNS_IP> <DOMAIN>     #Information
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dig MX @<DNS_IP> <DOMAIN>      #Emails related
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dig NS @<DNS_IP> <DOMAIN>      #DNS that resolves that name
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dig -x 192.168.0.2 @<DNS_IP>   #Reverse lookup
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dig -x 2a00:1450:400c:c06::93 @<DNS_IP> #reverse IPv6 lookup
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​
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#Use [-p PORT]  or  -6 (to use ivp6 address of dns)
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Using nslookup
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nslookup
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> SERVER <IP_DNS> #Select dns server
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> 127.0.0.1 #Reverse lookup of 127.0.0.1, maybe...
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> <IP_MACHINE> #Reverse lookup of a machine, maybe...
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Useful metasploit modules
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auxiliary/gather/enum_dns #Perform enumeration actions
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Useful nmap scripts
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#Perform enumeration actions
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nmap -n --script "(default and *dns*) or fcrdns or dns-srv-enum or dns-random-txid or dns-random-srcport" <IP>
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DNS - Reverse BF
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dnsrecon -r 127.0.0.0/24 -n <IP_DNS>  #DNS reverse of all of the addresses
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dnsrecon -r 127.0.1.0/24 -n <IP_DNS>  #DNS reverse of all of the addresses
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dnsrecon -r <IP_DNS>/24 -n <IP_DNS>   #DNS reverse of all of the addresses
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dnsrecon -d active.htb -a -n <IP_DNS> #Zone transfer
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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.
Another tool to do so: https://github.com/amine7536/reverse-scan​
You can query reverse IP ranges to https://bgp.he.net/net/205.166.76.0/24#_dns (this tool is also helpful with BGP).
DNS - Subdomains BF
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dnsrecon -D subdomains-1000.txt -d <DOMAIN> -n <IP_DNS>
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dnscan -d <domain> -r -w subdomains-1000.txt #Bruteforce subdomains in recursive way, https://github.com/rbsec/dnscan
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Active Directory servers
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dig -t _gc._tcp.lab.domain.com
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dig -t _ldap._tcp.lab.domain.com
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dig -t _kerberos._tcp.lab.domain.com
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dig -t _kpasswd._tcp.lab.domain.com
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nmap --script dns-srv-enum --script-args "dns-srv-enum.domain='domain.com'"
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DNSSec
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 #Query paypal subdomains to ns3.isc-sns.info
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 nmap -sSU -p53 --script dns-nsec-enum --script-args dns-nsec-enum.domains=paypal.com ns3.isc-sns.info
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IPv6
Brute force using "AAAA" requests to gather IPv6 of the subdomains.
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dnsdict6 -s -t <domain>
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Bruteforce reverse DNS in using IPv6 addresses
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dnsrevenum6 pri.authdns.ripe.net 2001:67c:2e8::/48 #Will use the dns pri.authdns.ripe.net
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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:
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dig google.com A @<IP>
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Non available:
Available:
Mail to nonexistent account
From book: Network Security Assessment (3rd edition)
Simply sending an email message to a nonexistent address at a target domain often reveals useful internal network information through a nondelivery notification (NDN).
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Generating server: noa.nintendo.com
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​
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[email protected]
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#550 5.1.1 RESOLVER.ADR.RecipNotFound; not found ##
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​
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Original message headers:
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​
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Received: from ONERDEDGE02.one.nintendo.com (10.13.20.35) by
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 onerdexch08.one.nintendo.com (10.13.30.39) with Microsoft SMTP Server (TLS)
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 id 14.3.174.1; Sat, 26 Apr 2014 16:52:22 -0700
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Received: from barracuda.noa.nintendo.com (205.166.76.35) by
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 ONERDEDGE02.one.nintendo.com (10.13.20.35) with Microsoft SMTP Server (TLS)
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 id 14.3.174.1; Sat, 26 Apr 2014 16:51:22 -0700
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X-ASG-Debug-ID: 1398556333-0614671716199b0d0001-zOQ9WJ
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Received: from gateway05.websitewelcome.com (gateway05.websitewelcome.com  [69.93.154.37]) by 
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barracuda.noa.nintendo.com with ESMTP id xVNPkwaqGgdyH5Ag for <[email protected]>; Sat, 
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26 Apr 2014 16:52:13 -0700 (PDT)
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X-Barracuda-Envelope-From: [email protected]
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X-Barracuda-Apparent-Source-IP: 69.93.154.37
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The following data in this transcript is useful:
Internal hostnames, IP addresses, and subdomain layout
The mail server is running Microsoft Exchange Server 2010 SP3
A Barracuda Networks device is used to perform content filtering
Config files
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host.conf
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resolv.conf
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named.conf
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HackTricks Automatic Commands
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Protocol_Name: DNS    #Protocol Abbreviation if there is one.
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Port_Number:  53     #Comma separated if there is more than one.
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Protocol_Description: Domain Name Service        #Protocol Abbreviation Spelled out
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​
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Entry_1:
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  Name: Notes
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  Description: Notes for DNS
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  Note: |
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    #These are the commands I run every time I see an open DNS port
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​
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    dnsrecon -r 127.0.0.0/24 -n {IP} -d {Domain_Name}
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    dnsrecon -r 127.0.1.0/24 -n {IP} -d {Domain_Name}
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    dnsrecon -r {Network}{CIDR} -n {IP} -d {Domain_Name}
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    dig axfr @{IP}
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    dig axfr {Domain_Name} @{IP}
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    nslookup
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        SERVER {IP}
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        127.0.0.1
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        {IP}
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        Domain_Name
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        exit
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​
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    https://book.hacktricks.xyz/pentesting/pentesting-dns
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​
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Entry_2:
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  Name: Banner Grab
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  Description: Grab DNS Banner
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  Command: dig version.bind CHAOS TXT @DNS
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​
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Entry_3:
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  Name: Nmap Vuln Scan
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  Description: Scan for Vulnerabilities with Nmap
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  Command: nmap -n --script "(default and *dns*) or fcrdns or dns-srv-enum or dns-random-txid or dns-random-srcport" {IP}
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​
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Entry_4:
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  Name: Zone Transfer
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  Description: Three attempts at forcing a zone transfer
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  Command: dig axfr @{IP} && dix axfr @{IP} {Domain_Name} && fierce -dns {Domain_Name}
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​
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Entry_5:
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  Name: Active Directory
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  Description: Eunuerate a DC via DNS
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  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}"
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Entry_6:
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  	Name: consolesless mfs enumeration
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  	Description: DNS enumeration without the need to run msfconsole
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  	Note: sourced from https://github.com/carlospolop/legion
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  	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' 
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