source: https://www.securityfocus.com/bid/3928/info

dnrd (Domain Name Relay Daemon) is a freely available, open-source proxy name server. It will run on a number of Unix and Linux distributions.

There is a lack of sufficient bounds checking in DNS request and reply functions. As a result, it is possible for a remote attacker to cause a denial of service to legitimate users of dnrd.

It is not known whether it is possible to execute arbitrary attacker-supplied instructions as a result of this vulnerability.

dd if=/dev/urandom bs=64 count=1 | nc -u 127.0.0.1 53 -w 1