191 lines
6.0 KiB
Markdown
191 lines
6.0 KiB
Markdown
# 53 - Pentesting DNS
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## **Basic Information**
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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. DN S translates domain names to [IP addresses](https://www.cloudflare.com/learning/dns/glossary/what-is-my-ip-address/) so browsers can load Internet resources.
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From [here](https://www.cloudflare.com/learning/dns/what-is-dns/).
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**Default port:** 53
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```text
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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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```
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## Enumeration
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### **Banner Grabbing**
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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.
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You can perform this query using `dig`:
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```bash
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dig version.bind CHAOS TXT @DNS
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```
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If that does not work you can use fingerprinting techniques to determine the remote server's version -- the [`fpdns`](https://github.com/kirei/fpdns) tool is one option for that, but there are others.
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You can grab the banner also with a **nmap** script:
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```text
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--script dns-nsid
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```
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### **Zone Transfer**
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```bash
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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 -dns <DOMAIN> #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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```
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### More info
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```bash
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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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#Use [-p PORT] or -6 (to use ivp6 address of dns)
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```
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#### Using nslookup
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```bash
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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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```
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### Useful metasploit modules
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```bash
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auxiliary/gather/enum_dns #Perform enumeration actions
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```
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### Useful nmap scripts
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```bash
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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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```
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### DNS - Reverse BF
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```bash
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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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```
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Another tool to do so: [https://github.com/amine7536/reverse-scan](https://github.com/amine7536/reverse-scan)
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You can query reverse IP ranges to [https://bgp.he.net/net/205.166.76.0/24\#\_dns](https://bgp.he.net/net/205.166.76.0/24#_dns) \(this tool is also helpful with BGP\).
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### DNS - Subdomains BF
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```bash
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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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```
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### Active Directory servers
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```text
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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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```
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### DNSSec
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```bash
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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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```
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### IPv6
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Brute force using "AAAA" requests to gather IPv6 of the subdomains.
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```bash
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dnsdict6 -s -t <domain>
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```
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Bruteforce reverse DNS in using IPv6 addresses
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```bash
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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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```
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### DNS Recursion DDoS
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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.
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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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```bash
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dig google.com A @<IP>
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```
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**Non available**:
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**Available**:
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### Mail to nonexistent account
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From book: Network Security Assessment \(3rd edition\)
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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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```text
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Generating server: noa.nintendo.com
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blah@nintendo.com
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#550 5.1.1 RESOLVER.ADR.RecipNotFound; not found ##
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Original message headers:
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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 <blah@nintendo.com>; Sat,
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26 Apr 2014 16:52:13 -0700 (PDT)
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X-Barracuda-Envelope-From: chris@example.org
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X-Barracuda-Apparent-Source-IP: 69.93.154.37
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```
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The following data in this transcript is useful:
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* Internal hostnames, IP addresses, and subdomain layout
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* The mail server is running Microsoft Exchange Server 2010 SP3
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* A Barracuda Networks device is used to perform content filtering
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## Config files
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```text
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host.conf
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resolv.conf
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named.conf
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```
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