Check if the DNS servers are vulnerable to version queries.
Analyze the reported version for vulnerabilities and available exploits.
dig @<ipaddress of nameserver> version.bind chaos txt ;; ANSWER SECTION: version.bind. 5 CH TXT "<span style="color: #ff0000;">PowerDNS Authoritative Server 3.3.3</span> ([email protected] built 20150610125050 [email protected])"
Linux / Windows
nmap -sSU -p 53 --script dns-nsid <ipaddress of nameserver> Nmap scan report for ********* Host is up (0.073s latency). PORT STATE SERVICE 53/tcp open domain 53/udp open|filtered domain | dns-nsid: |_ bind.version: <span style="color: #ff0000;">PowerDNS Authoritative Server 3.3.3</span> (firstname.lastname@example.org built 20150610125050 mockbuild@
We can also perform the DNS version check in a passive way (indirect) via an online service:
DNS Report on http://www.dnsstuff.com/tools
It looks like we found an older version of PowerDNS with known vulnerabilities:
The documentation notes that the reported version can be changed and version queries can also be blocked.