Metasploitable/DNS Bind

Searching for Exploits

Searching for exploits of the DNS service that is running, ISC BIND 9.4.2, we find the following exploit: https://www.exploit-db.com/exploits/6122/

This exploit is labeled auxiliary/spoof/dns/bailiwicked_domain. It allows us to insert malicious DNS records into the DNS server.

DNS Exploit: bailiwicked domain

More information:

This exploit targets a fairly ubiquitous flaw in DNS implementations
which allow the insertion of malicious DNS records into the cache of the
target nameserver.  This exploit caches a single malicious nameserver
entry into the target nameserver which replaces the legitimate
nameservers for the target domain.  By causing the target nameserver to
query for random hostnames at the target domain, the attacker can spoof
a response to the target server including an answer for the query, an
authority server record, and an additional record for that server,
causing target nameserver to insert the additional record into the
cache.  This insertion completely replaces the original nameserver
records for the target domain.

To interpret:

• Metasploit induces the target nameserver to ask for a bunch of hostnames at a target domain.
• Metasploit then sends fake responses from the target domain back to the target nameserver in an attempt to confuse the target nameserver.
• When the attack/spoofing is successful, the target nameserver will receive a new authority server record (faked by Metasploit), and will insert this new record into its DNS cache.
• This means the target nameserver has a new DNS record for the target domain, containing whatever DNS servers were set in the Metasploit attack.
• Now, anyone requesting the target domain from the target nameserver will actually be routed to your (malicious) nameserver, where you can tamper with the request before forwarding it along.